I have ADHD, and two kids with ADHD, so I can relate. I will say that my oldest, at 5 just wanted to have fun. She listened to the coaches (like you said your daughter pays attention when the coaches are working with her) but she lacked any kind of focus until she was 7, on her second year of the team! The first year she didn't really fool around, but she didn't put any effort into it. She rarely medalled and that was okay with her. Her second year we told her that if she wanted to do something else, we could quit gymnastics, but if she was going to stay on the team, she had to really work hard. She did. She won a state championship too.
As for the diagnosing, etc. My kids can't be medicated because they aren't heavy enough. The meds take away your desire to eat. If your child has trouble putting on weight, medication will make it worse. I take meds for mine, and they do help me concentrate a lot better, but realistically, I can get by without them, and they are generally (although not always, depending on the prescription) expensive.
I would give it another year before you start expecting everything to "click". If it gets worse, or you see problems in school, definitely get it checked out, but know that medication is not necessarily the way to go. Also, routines are everything for those of us with focus issues. As often as possible, try to get everything done the same time each day. Instead of saying "go put your dishes away" ask "what do you need to do next?" I know transitions in our house are the hardest to deal with (my one son doesn't have ADHD, and he can multi-task really well...problem is he will start the other one playing and all pandemonium breaks loose!)
Sorry to write you a novel. Hope this is helpful!
Snowbound