Heidi is 12, almost 13 and going downhill. She still likes to swim and I have been trying to take her swimming as much as possible. We park as close to the swimming place as possible. It is probably 1/4 mile walk from the car. She is having a terrible time getting up the incline from the lake and then back to the car. Yesterday, her back legs kept giving out and we had to stop and rest numerous times. Also, she fell several times while trying to run up and down the beach. But going there and the swimming makes her happy. Do I keep taking her or play it safe at this point?