I was in my late 20s before I was diagnosed with fibro. I've found that the biggest contributors to my pain being manageable are:
DON'T skimp on sleep
Spend time outdoors (it might just be because this makes me happy and relaxed, but it seems to really help)
Eat a good diet (a keto adjacent, high veggie, low carb diet seems to make my body happiest, but everybody's nutritional needs are a little different, so you do you)
Set achievable goals for your day but try to structure them so they're flexible and have a few stops built in, depending on how you're feeling. (e.g., over the weekend my husband and I wanted to do two large outdoor chores - we did all of one and about a third of another, and stopped at a sensible place so we could continue later, when continuing wouldn't steamroll my energy for the rest of the day)
Take time out every day to do something you enjoy, even if it's unproductive. I spend time with my chicks or bottle calves, or play a video game. Stress makes my fibro go crazy, so managing my stress is important for me.