Wow. The first person is so not true. You can start recreational ballet at any age if you have the passion for it!
You aren't too late at all. Sign up for some teen or adult beginning ballet classes. Lots of studios have them now due to all the people starting at your age and even older. You won't be stuck with little kids, and you'd be with kids your age and level too. :)
Pointe is only allowed after you've taken a minimum of at least 3 years of ballet with several classes a week. You have to have good strength and strong technique and be at least a high Intermediate level. Pointe is exactly like ballet except in different shoes and on your toes. As I like to say, if you can't do it on flat, you'd never be able to do it en pointe! If you're patient and work hard, you will get to pointe.
I don't know of any youtubers i'm sorry. But work on flexibility at home. Do the frog stretch, straddle, touch your toes, etc. Splits aren't needed at all in ballet, I don't know why everyone thinks they need them, but if you want to work on those too, then you can. Just don't push yourself! You could get hurt and you don't want that before you start ballet.
Hope I helped! :)
Ballet dancer for 12 years, en pointe for 6 months.