Maybe posting this in the Foyer would be a better place?

First, it's great you are vegan, regardless of it only being a month. 

My advice: do what's right for you, and don't let what others think (or what you think others think) about it veganism affect you.  Like you said, you are doing it for animal cruelty (and health reasons), so *that's* what matters. 

You can always reply to them by saying something like, "yeah, I used to eat those things but I'm aware now of the animal cruelty/health issues that go along with those foods, so I'm switching to a compassionate, healthy way of living by being vegan." 

You never know, you might inspire some of them to go vegan as well.

"I've had a change of heart about my lifestyle."  If people want to participate in a polite conversation about why, that's alright.  If they give you a hard time, tell them to go ____________ themselves.  Or you can just tell them it's not their business when they ask why.

I don't think asking why you're doing something different is making fun of you. Even as a vegan myself I'd still be curious about why someone else changed their mind about food or diet (or any lifestyle choice), especially if it was someone I knew well. People don't always have negative reasons in mind when they question things... But if they give you a hard time, just flat out say you're willing to explain your reasons but you're not interested in starting an argument. Being arsey won't get either of you anywhere!

Everyone has to start somewhere. When I first switched to veganism, some people in my family wondered why, too, but I just told them, it was the next logical step for me, and after reading about the cruelty inherent in dairy and egg farming, I just couldn't do it. Sometimes I just said "Well, I just don't want to eat that stuff anymore." People are curious creatures, even I want to know why other vegans made the switch sometimes. If they do make fun, just say "It's a personal decision, and this is the right choice for me. You can do what you want, but I'd appreciate it if you respected my choices, thanks."

First of all, where are you in life? School obviously, but high school or college/uni? It relates to how open people are to new ways of living life.
I'm with pretty much everyone here. Just say you've just started and it4s for cruelty/health reasons. If they want to know more elaborate, if they don't ask don't tell. If they make shitty jokes, sit somewhere else for lunch.

As you live in this world you will start recognising certain people and their reaction on your, obviously very extreme to them, lifestyle. Some will mock, others will understand. And with that understanding will come a development in how you answer it. We, old old people, know tons of funny quips in which to tell people off for [some misunderstanding/prejudice/whatever], but that requires time and being confronted with all those stupid questions omnis are going to ask you.

- Wally

For now, you have made a big decision: Give your friends/schoolmates time to understand

What has worked for me in deflecting attention away from what I am not eating is to whip out what I am eating.  Choirqueer has it right - hand out cookies, muffins, scones or any other kind of vegan breakfast goody while they are eating breakfast sandwiches.  That way, you are all still eating together, and your food will be tastier.  The same thing at lunch, dinner, etc.  If people see you eating delicious food, it becomes about what you are eating and not about what you are not eating.
People are bound to be curious whenever someone they know well makes a lifestyle change.  I wouldn't automatically assume that they are making fun of you - they may just be trying to get their heads around a concept that is new to them.   Smile, educate, hand out baked treats.  You will feel more comfortable in no time.
Congratulations!

you will always have questions from people you meet.  All my friends and family are used to my lifestyle, but everytime i meet someone knew and veganism comes up, they always have tons of questions.  I actually like talking about it, as long as they open to hearing about it.

I'm with some  of the other people who responded - it doesn't sound like they're really making fun of you so much as they're asking questions (and/or maaaaybe trying to catch you out on some kind of ethical inconsistency). The best thing you can do is just have your head on straight and keep your cool. It's totally normal and okay for your friends to ask you about your new dietary choice; it actually gives you a great opportunity to tell them in a calm, non-preachy way about why you think veganism is awesome. The worst thing you can do is get stressed out and defensive. I know lots of people talk about "comebacks" and coming up with snappy/snarky answers to annoying questions about veganism, but frankkly, I think that probably just makes vegans look kind of defensive, not awesome. Remember that they're just questions and that the only person's behavior in that situation that you can control is your own, so stay calm, answer the questions, and don't sweat it too much.

Good job on going vegan, also, and welcome to the PPK!

+1 to just politely saying you've decided to switch to veganism.

chatter710 wrote:

Just tell them you've changed. You're vegan now. Screw your past. Or, more eloquently:

Ralph Waldo Emerson wrote:

Wise men are not wise at all hours, and will speak five times from their taste or their humor, to once from their reason.

Blaise Pascal wrote:

Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.

Excellent quotes, chatter!

designedtobekind wrote:

Everyone has to start somewhere. When I first switched to veganism, some people in my family wondered why, too, but I just told them, it was the next logical step for me, and after reading about the cruelty inherent in dairy and egg farming, I just couldn't do it. Sometimes I just said "Well, I just don't want to eat that stuff anymore." People are curious creatures, even I want to know why other vegans made the switch sometimes. If they do make fun, just say "It's a personal decision, and this is the right choice for me. You can do what you want, but I'd appreciate it if you respected my choices, thanks."

This is the way to go – no question.

wasteland wrote:

Sorry if I post this topic in the wrong section.
Wow! Thank you so much for the suggestions. I really appreciate it! It makes me think more. Sometimes, it's hard to put it in words. Great advices! I'm definitely going to note all of them. I'm so dumb for not figuring this out earlier.

You're not dumb; you're just new at this (which probably means that when you're vegan for longer, you'll think past-you was dumb). Make note of the quotes. If they don't exactly help, they sure as hell will impress people.