Given this case that you are going to play paintball game and you are a very highly near-sighted person, it is better for you to choose wearing eye contacts instead of frame eye glasses. First of all, eye glasses are not very convenient for you when you are playing paintball game, the frame keeping slipping from your nose making you from time to time hold back the frame in the right place with your hands, which could definitely affect your action and make you feel awkward and inconvenient. The other advantage of wearing eye glasses during a paintball game is that the glasses are fragile and will be easy broken during the game in case of collision or stumbling. Therefore, you can choose wearing a pair eye contacts which can help you get rid of the troubles of wearing eye glasses. Eye contacts will not at all affect you under a paintball mask, and they are quite safe if you choose the right contacts. For further information about eye contacts, you can refer to the following website and have a look.
It will be uncomfortable for you to wear glasses under a paintball mask. I suggest you to wear the contact lenses when you have the paintball game. You could just buy the daily contact lenses which will be thrown away after a day. You could take this idea into consideration. The contact lenses will make you see things clearly.
Ok, it sounds really interesting! But you should know that paintball mask could make you unable to wear glasses, for there would be no spaces for a pair of glasses. However, my advice for you is to get a pair of contact lenses from a local optical store, those stuff could be compatible with paintball masks. Just enjoy yourself with them tomorrow. And of course try to make clean use of the lenses.