I think I might have Vaginismus

So I'm 15 years old, and I have never had any sort of sexual intercourse at all. But recently I was curious on figuring out how all of that works in the shower, so I tried to insert my finger into my vaginal opening. It was extremely tight, so much so that it hurt with just the tip of my pointer finger, and I'm wondering what I should do now. I told my mother (I lied and said I tried to use a tampon bc I'm not telling her about that 😭) and she said it will get better with age once I'm less anxious about it, but I'm not sure. Any tips?

Update: I attempted to actually use a tampon for the first time, and with about five minutes worth of struggle I got it in. (I actually had to lay down on the floor to insert it) But it definitely hurt pretty bad. My mother is scheduling me a gyno appointment, so I'll update again after that :)