Toy won’t fit

Hi, my dildo won’t fit no matter what I do. Last time I had sex was 3 years ago so I know it can fit things in it but for some reason it won’t now. I have a slimline dildo so it’s thinner than usual and I use lube. I make sure to orgasm before even attempting to put it in but still nothing. It feels as if a wall is blocking it past a certain point but this doesn’t apply when I use my finger, so can somebody tell me what I can do to make this work?? Also I’m not the best at anatomy but I need to know if the vaginal opening is like a black hole or if it’s meant to have that wall like thing blocking it.