I'm 13 Years Old, And My Ankles Are Red And

I'm 13 years old, and my ankles are red and slightly swollen. They are red all the time but only swell up a little when I get out of a hot shower or the hottub in my backyard. I read online in many places that this is a symptom of CHF, but I don't have enough information to believe anything yet. What is going on?