9F daughter keeps adding to times

My 9F daughter joined the swim team last summer and had a blast. She decided to join the yearround swim team in our neighborhood after the summer season ended. It’s been 6 months and we’ve gone to around 5-6 swim meets. I noticed that she has been adding time to almost all her events over the last 3 months. This culminated in her last swim meet, where she added at least a second to every event she swam. She goes to practice 3-4X a week. Why is this happening? I don’t know much at all about swimming but I assumed your times get faster the more your practice. That is what happened during the summer season. I’m starting to wonder if she needs to take a break or maybe swimming isn’t her best thing to focus on. She loves swimming but is also feeling discouraged.

Edit: wow! Thank you for all the amazing insights and advice. I’m so glad to hear of so many other kids having non-linear progression like this. So many of her swim friends just seem to get better and better but they also all have been swimming for multiple years. I will also back off on the meets and practices and make sure she focuses on having fun more than anything.