Strap on, strap off.

Y’all! I’m very very tight. I’m barely a virgin & have been fingered plenty of times, but my significant other & I want to start using a strap on, it will be my first time using 1. I want to do it more, my significant other just wants me to be pleased. I’m lowkey scared it won’t fit, any suggestions aside from buying a new strap?? TYIA