Would I be able to go en pointe successfully in 10th grade?

I have been taking dance since I was 3. I quit ballet after 7 years. Now I am 13, in 8th grade, and want to do ballet again. I take ballet barre right now, which is a non serious ballet class, but we still do everything you would in a normal ballet class. I want to take the serious ballet class next year, in 9th grade, and hopefully be en pointe by 10th grade. I do have the proper technique for everything and am flexible (also i can do a double), but I could get stronger. Would I be able to go en pointe successfully in 10th grade. Also, what should i do to make my ankles/legs/core/arms stronger?