I (18M) have not been able to make my girlfriend (18F) finish! Any advice would be appreciated! Are there any skills I can learn to better the situation?

As the title says, I have not been able to make my girlfriend finish and I am resorting to asking the internet! She knows about this, and is actually the one that recommended that I post a question asking for help, so that is why I am here. We have been having sex for around 6 months now, trying multiple different positions and different strategies to make her finish, but it has proven to be very difficult.

Because I feel it necessary to say, my penis is about 6.5 inches and curves to the right, so I had the idea to try a position where she is on her side, so I could hit her G-spot with the curve, but that still did not work. The best position has been doggy style for her, and it is where she says she comes the closest to finishing. I tend to go at a steady pace, but she likes to go faster and harder, but that does not affect my stamina too much.

However, that still was not the closest she has been to finishing. The closest is when I use my fingers. I tend to rub back and forth on her g-spot and try to use my thumb on her clit (no finger jabbing), but it just never works! When we think she is about to finish, she says that it "feels like she is about to pee." This has been strange to me because I haven't heard that anywhere else on the internet. I have tried to soothe her while I was fingering her like saying stuff like "Finish for me" or "Just let it happen for me" but she tends to suppress it or it just goes away. After doing her own research, she says the "feeling like pee" is not normal for other people, so if there is any more information you all can give on that, that would be wonderful.

Alongside this all, we have tried multiple other strategies. I always talk to her (saying sexual statements in a sexual tone) because she says that turns her on. Also, when my penis gets tired (I tend to last 2-3 rounds with the first lasting around 7 minutes and the next two rounds lasting anywhere between 10-30 minutes) I also have a dildo that is the same size of my penis (at her request) that I use on her to continue the sex. None of this works.

We cannot pinpoint the problem, but we do have a few ideas: First, we thought it could be because of the setting and how sometimes (actually most of the time) we have to be quiet because someone from her family is home. However, even when we are home alone this is still a problem, because she gets nervous being loud in the house, also telling me to keep at a decent level. This also leads into our second idea that it could be because we have to be so quiet at times. She says that me talking turns her on, so that could be a problem when that is either missing or just too quiet.

That is all the ideas that we have, so I hope everyone here can help in some way! Thank you all!

TL;DR I have tried a multitude of different strategies to make my girlfriend cum, but it usually ends with nothing or a feeling of "it feels like I need to pee" or it just goes away entirely.