[Scared to have sex with my friend!] Advice needed!

Ok, I have a bit of an issue which I haven't really confronted properly for years. My Dick is small, well tiny really- just under 3 inches erect and I'm 24 years old so I'm guessing it won't get any bigger. I need to make a decision whether to have sex with my friend but am really scared about it...

Anyway I have kept my small penis secret pretty much my entire life, I've avoided sex completely apart from once when I was on holiday and drunk. Basically met a girl clubbing when I was 18 in Greece and took her back to my room. I can still remember the look on her face when she saw it of pure disbelief. I wasn't really sure what to expect but seeing as I was on holiday and would probably never see this girl again I thought I would see what happened. We tried having sex but I could barely penetrate her and she was laughing so much it just got humiliating.

Wind forward 6 years and I like a girl and I know she likes me. In fact we've been friends for a few years now and feelings seem to have developed on both sides. I know she is way more experienced than me and what worries me is I remember her drunkenly telling a story about this guy she had a one night stand with who she described as "huge" downstairs and she said the sex they had was mindblowing. I'm worried that she is really into huge dicks and I am the total opposite. We've been flirting for the past two weeks and we have been sexting and she said she'd love for me to send a dick pic. I haven't- and said she'd have to see it for real which she said turned her on.

Anyway, I'm pretty sure this will lead to us having sex or at least I know that's what she wants. My question is, do I be completely upfront about it or say nothing and wait for her to find out naturally?

Another question is the sex I had 6 years ago was so bad I'm worried about this too. Are there any positions that make sex easier for someone with a small penis? What is the best to achieve optimum penetration? We mainly tried missionary but I couldn't really penetrate at all properly.

Thanks in advance