First of all, congratulations on your bushy bush, lady! I’m so glad you’re enjoying your womanhood.
Having gone to Rosedale, I doubt that anyone would seriously care. People in the younger grades might, because they haven’t shaken off their mainstream social conventions yet, but the upper grades probably wouldn’t even blink at underarm hair.
Part of growing up is doing stuff that you feel strongly about, especially when it scares you. Social pressure is an example of a bad reason to give up a goal or desire. Seriously, when I look back on the choices I’ve made, everything that I decided not to do because I thought someone would judge me is something I wish I’d done anyway.
I think you should do it if that’s what you want to do. And then celebrate your wild sexy beauty in every way you can. Have a friend take raunchy photos of you, wear sleeveless shirts with siren red lipstick, smile at anyone who gives you a weird look. Having body hair as a woman is an incredibly brave choice in our culture, and you should regard yourself as a very courageous person for this (and for other things, I’m sure!).
If you’re looking for a role model in your hairy ways, look up some photos of Amanda Palmer. She rocked armpit hair and a see-through dress at the Golden Globe awards. It doesn’t get much braver than that.
Good luck, love! Let me know how it goes.