Penetration not my thing?

Hey guys. So, I’m a lesbian and recently lost my virginity to my girlfriend through oral sex. I can definitely orgasm through clit stimulation and oral and my gf makes sure that I do. However, my gf can have all these amazing orgasms from penetration and fingering, but I can’t seem to have much luck. Her inserting even 1 finger is pain (mainly around the entrance of my vagina) and once it is in, I either feel nothing, or it’s uncomfortable and sometimes I feel a little nauseous afterwards, hence why we don’t try it that often. Whenever we try DO it, I’m plenty aroused so I don’t think that’s the issue, and we definitely use lube to try and make it more comfortable. Does anyone else feel this way about penetration? It’s not really a big deal because it’s not sacrificing any pleasure on her end, but I was just wondering if I was alone in feeling this way.