With a minimum of 4 or 5 hours a week of ballet, you should be able to go en pointe in about 3 years. Unless you are not going to a good school and then it would be less. Your first school looks like they wanted to put you en pointe at 10.
At that age your foot plates haven't finished growing and going en pointe at that age can have serious consequences for your feet for the rest of your life. If that was the case, than I am glad for you that you dropped out when you did. Real ballet training starts at age 7 or 8.
Before that is pre-ballet because the body isn't really ready to handle ballet positions correctly. Ballet is more than just being flexible. You need to be strong.
You can be totally flexible but if you have no strength you won't be able to use it. You must have strong feet, ankles, legs, core, balance and always work engaging your turnout. You must also have strong ballet technique.
If you cannot do it on flat, you won't be able to do it en pointe. Instead of worrying about when you will go en pointe, just enjoy your ballet classes and the rite of passage of learning how do be a strong dancer. Before you know it, you will be ready and be able to go en pointe.
I got my pointe shoes in the beginning of 7th grade and im in 8th this year, and trust me I'm still wobbly sometimes, can't turn more than once, and people say I'm good. The trick is how strong you are.... You'll know the ballet steps already, so spend a few months on demi pointe, and work with a good teacher, once she approves you make sure you believe you are ready too. I'd say if you can balance for 10 seconds on one leg in posse you have the ankle strength and balance.
To become stronger go to academy and get some yoga stretchy bands(they come in 3 packs with different thicknesses) and pointe and flex your feet in them while sitting with your leg straight for a few minutes each night. For flexibility do a jazz split every day and hold it for a minute. You'll be very flexible very quickly!