Shy guy wanting advice.

I'm new to this but I am wanting some advice. I'm 25 and I have strugged to deal with having a larger than average penis. I'm not very experieced and I'm embarrsed about my body. I've met a women albeit 10 years older than me and we are getting on well. But sex can be painful for her. I'm 16cm long soft and 27cm erect. We have tried lube and always have foreplay. How do some larger guys deal with this? I'm trying not to go too deep.
I've been with women who have said no to sex once...

Shy guy wanting advice.