I agree with Amy about the face. Also, being female is more than looks! HRT isn't just a physical change, and you will change mentally. HRT affects the brain. And no matter how male you try to look, the feminine is going to come out after several months. Girls will probably notice first, and then guys (they will probably just think your gay, and then beat you up for that, too).
I know too many people who decided to go on HRT thinking they could hide things just to find out that they couldn't. People notice. Your body changes, your mental changes, and even the way you smell. Believe it or not, people are going to pick up on your smell and realize something is going on. I have one friend who just started HRT a few weeks ago and isn't full time, going in boy mode at work -- people keep looking at her weird, noticing that there is something different about her.
But yeah, you can try the baggy thing and all of that for a year and a half. It's going to be very hard. And as you go along you'll keep waking up in the morning wondering why you're living your life for everyone else and yearning to be the woman you are. HRT doesn't help you hide. HRT will only make you want to come out faster. And honestly, bad people will be their after you graduate and for the rest of your life. Do you want to live your life in fear of them and give them that kind of power? Or do you want to take control of your life and be all that you can be?
It's really upto you, and it's your life. Talk to a doctor/therapist about this and your hormones. Consider other options of you choose HRT (like another school, etc). If you feel that you can get away with things with baggy clothes, emo hair, and facial hair, and being someone you're not, go for it. It's up to you to decide what you will do. I have my opinions, but those are just my opinions -- it's up to you, not me.
Good luck in what ever you choose,
--natalie 🙂