Apple Watch not counting exercise correctly

My Apple Watch is a series 2, so pretty old. It’s a hand-me-down from my mom and it’s worked great up until now. Recently I was in Disneyland from opening at 8 until 10pm, so over 12 hours. If you’ve been to Disneyland you know how many steps you take there. When I got home my exercise ring wasn’t even closed! It said I only got 24 minutes of exercise which I can’t even see being possible. Is it because I didn’t ask it to log the steps as exercise? It’s never been a problem before. Is there something I can do to fix it or is it just time for an upgrade?