SO MUCH PAIN !! PLEASE HELP !!

I’m 16 years old and I’ve never masturbated by fingering myself, but I wanted to try something new. I tried so hard to find the opening and put a finger in, but it was hard and I couldn’t find it. It also hurt a lot. I spent twenty minutes trying to put a finger in, but I failed and it hurts so much I started crying. I’m desperate for answers, so please help me understand why it is so hard to put a finger in. :(