It isn't a good idea! I'm a hairdresser, I struggle cutting my own hair! Ask your friends where they get their hair cut, let a professional do it for you. If you mess it up, you'll have to pay to fix it. Might as well get it cut the way you want it the first time! Good luck!
It's kind of hard to explain. I go to the hair dresser and i also cut it myself. But I only do my bangs and fix some layers. It's kind of like a guys haircut really. My hair is long but in my picture it looks short, because I tied my hair back. Btw having glasses and trying to have that type of hairstyle is really hard. Watch some videos on YouTube. Check out CassieEatsYou's channel, she has a really good video on how to cut your bangs and make them go forward and all the good stuff lol!