If you aren’t sure it’s really a cavity, and getting a filling bothers you, get a second opinion. Fillings don’t last forever, and can be less sturdy than natural tooth.
Sometimes, when the new dentist finds a ton of stuff, it's real.
My husband and i moved to a new town some years ago. We doing a dentist and both set up appointments. He hadn’t seen a dentist in a while, I’d had regular dental care.
His appointment was first. They found so many problems they only really examined one side, and had him return for a second visit to examine the other side. And they scheduled a ton of follow-up work. I wondered if they were just looking for revenue. But i went a few days later, and they said, “looks good, we should keep an eye on [the tooth my prior dentist was keeping an eye on]”. I think they were completely legit, and my husband had a lot of tooth problems.
On the other hand, when my lower wisdom teeth came in, lo these many years ago, my [then new] dentist immediately diagnosed cavities. I let him fill the first, but i felt suspicious with the second. I asked to see the x-ray, he said it would take a day to be developed, he just felt squirrelly to me. So i said no, and found a new dentist.
The tooth he filled needed a partial crown when i was in my 40s. The other tooth was discolored, but every dentist i went to for decades poked at the surface and moved on. I finally needed a small filling in it in my 60s. I’m really glad i didn’t let him drill it.
Admittedly, i have good enamel. (So my several dentists tell me.) But you probably do, too. Drilling is destructive.
Anyway, DON’T ignore it for 15 years. But ask the dentist what they think they should do. If it’s just sealing it, (non destructive) go for it. If it requires drilling away a chunk of your enamel to make room for the filling, i don’t think it’s crazy to get a second opinion.