The best advice I've managed to get in regards to growing and cutting a beard is this: When you are considering about changing your look (aka cutting/shaving stuff off), always spend proportionally the same amount of time as it took you to grow it. So, if it took you 3 months to grow a beard, spend at least 3 weeks thinking about it. NEVER cut your beard the same day or even the following. Sleep on it. You'll regret it instantly if you do it too hastily. It's YOUR face and it's YOU who gets to enjoy looking manly. I cannot tell you wheter you should or should not shave stuff off, just telling you to take your time when considering your options. Your beard won't run away while you are pondering about things. It won't, however, grow back fast if you make a mistake.
That said, here are my personal thougths on what people have said here:
If there are school rules about being clean shaven then you should just shave.
I got kicked out of school for not cutting my hair, made a big deal about it being sexist that femles can have long hair but males cant.
I want to say that's BS on school's part but then again there are different schools... But in the end, school is just a temporary place to attend for a relatively short time. Don't get into trouble on purpose.
You might want to read into beard/moustache maintenance if you do end up keeping it. As with any excessive body hair, it'll look much better if you actually take care of it. People not liking it might be because it's new and different, or because you don't take care of it and it looks horrid as a result.
Nothing more to say to that. People(/chicks) like men who are able to take care of themselves more. In general.
You may consider getting a trimmer and keeping at a perpetual 5-o'clock shadow. Depending on your facial structure it may strike a nice balance between beard and baby face.
I would consider that lazy and untidy.
I find beards are itchy. I've had beards and moustaches and even when I did for months, the day I shaved it was like "finally, no more ITCHING!".
Beard itch can be a problem when first growing beard out. As it grows, the very tips of the hairs are sharp due to shaving. As time passes, the tips begin to dull and become less irritating. Also, adding beard oil can really help too to make the hairs softer. If you cannot find real beard oil, just add a bit of olive oil or coconut oil to your beard before shower. A dap can help even after the shower, just do not overdo it. Oily beard is gross. Also, never use the same soap/shampoo on your beard as you use for your hair. Those are tow very different hair/skin types. Use only the mildest of things for your beard. You don't wash your face with normal body soap either, now do you? (again, a very differnet skin type)
If your going to trim a beard or any real growth then buy a cheap DE razor, there so much better than cartages, it untrue.
If you do wet shaving, invest in some proper equipment. And by proper, I mean DE razor. You get better, smoother and less irritating results with less blades you use. Don't buy into Gilette propaganda. Having 10+ blades is only going to do damage on your skin. Also, do not use shaving cream foams that come in a bottle. They often have stuff in them that only dry out your skin. Prefer the old fashioned creams that require a brush to use.
If you later on in life decide to go with a full beard, I highly recommend watching Beard Baron's videos on YouTube. Almost everything I listed here I learned from him (as well as from others).