Ballet dancer's are often referred to like athletes, because it is a very physical skill to accomplish the technique and especially dance professionally.
You have to be incredibly strong and it takes lots of power in the muscles to dance every ballet move.
You may hear your teachers say you have to get stronger in order to start pointe, or get stronger to move up to the next level.
Nearly every dancer I've met owns some sort of physical therapy equipment to help them progress. Especially, the resistance bands are the key ballet supply to have.
Take a look here at the different equipment you can get -
Keep working hard and remember, time and patience is the most precious thing to help you improve!
P.S - The quote of the day is: “Nothing happens in the body without happening in the brain first... dancing is 95% mental."