"Bitch doesn't let me in." Idk, maybe you're not knocking hard enough? ?
But in all seriousness, yes, that is their default (not in heat) position. There are tricks to getting in, it really isn't that hard once you learn the maneuvers. But the most important questions is, does she want you to come in? Does she orgasm from fingering and oral? It's should be easy to tell while fingering, she should go from moist to very wet very quickly.
If you're able to insert your fingers in her vagina, does she resist you? Does she look uncomfortable? If she comfortable with this, is she realistically too tight for your penis to comfortably fit in, so you don't hurt her? (Have fun explaining that one to your vet.)
If she looks to be in the mood and she can accommodate you then, congrats! I usually reach around her waste and locate her pussy with one hand and then insert my finger into her vagina. Using my other hand I guide my penis into her vagina using my other hand I have inserted as a guide. Once my tip is in, I push up and then in, aligning the tract.