Okay, for F 21 here. I exercise often and can do like 50 pushups in one go and around 10 chin ups (pull ups are hard for me) in one go. I did try dips but somehow they feel difficult... I thought I would be able to do dips since I am good with push ups and chin ups. Not very flexible, like I can't do the splits or the butterfly properly. And I don't have much stamina, like I can't run non-stop for even 20 mins.

What I wish to focus on: Flexibility (I really want to be able to do the splits) and strengthen by back more. And build up stamina.

Sorry for the long post, but I would be sincerely grateful if you guys could guide me on starting calisthenics