inexperienced help

Okay. So, I'm currently in a long term relationship with honestly the best guy ever. other than it being long distance, it's probably the healthiest relationship I've been in. We're meeting up at the beginning of June and it's more than likely going to end up with us having sex. I've only had sex with one guy before when I was 23(25 now), and he insisted he was 10 inches but was more so around 5 and half? LONG STORY SHORT, I am inexperienced. Currently my guy and I have been sexting and sharing pictures. I cannot ignore the fact that his penis is pretty big. He says it's 9.5 inches and I can believe it. He's also 6'4" and got a little dad bod starting, it's so cute. I'm 5'5"-5'6" and definitely overweight. Are we going to face any position issues with the height difference and weight difference? Does anyone have any tips or tricks that could help with making it enjoyable for both? I over think and I'm pretty sure I'm going to overthink this so much I'll be so nervous by the time it happens it won't be enjoyable. P.S. He's also a virgin, so how can I help him and make him comfortable? I want to make it as enjoyable as possible for both parties. Thanks.