I am 16 and deciding to take ballet for the first time.?
You should take beginner teen ballet. Drop in basis means that you pay for each individual class and can start and stop at any time. That is also called an open class. In most studios with kids, they must pay for the entire session and there is a recital at the end. Open classes are much better for learning. They may have a class card where you can get a discount if you buy ten classes at a time or something like that.
It is possible with time and by adding some extra classes you could go en pointe. As far as being a professional ballet dancer it is really to late at 16. Here is an answer I gave to someone else who just asked this question who is 15. Here is the REAL deal about becoming a professional ballet dancer, based on my experiences with the world of professional ballet.
Most ballet dancers have been training from age 7 to 11 the latest and dancing 20-30 hours of class a week at a major ballet academy. By 16 their training is pretty much complete and they become apprentices with the affiliate ballet company by 17 and corps. de ballet by 18. Because a ballet dancer's career is short, many retire around 30 if not earlier do to injury.
No ballet academy will train anyone your age as a serious prospect for their company. The would do it for a boy however because it is different with men because they do not dance en pointe and do not have to be quite as flexible. To get into a great ballet academy that would be required to get the training you need you must have the following. Feet with super high arches and a top bump, long hyper-extended legs, perfect turnout, long stretchy achilles tendons, short torso, long neck and small round head. You also must have great facility and musicality. Height and weight also figure into the equation. Even with all of that and all the training, many still don't make it. There just aren't enough jobs. NYCB laid off 11 dancers at the start of this last season. There have been the occasional dancer with a perfect ballet body etc. who have started at 13 and became a prima ballerina, but that is a rarity (Michelle Lucci.) Anaheim ballet has a dancer (with not such great technique) who started even later, so it may be possible for a small company being in the corps de ballet (not a principal dancer) if you have perfect everything else. Had she started earlier she may have gone much further.
NO REASON YOU CANNOT DO IT FOR FUN! Take class and have a great time dancing!