I was 20 when I lost my virginity too, and my first bf was sure I was 'a pro'. Not as in an expert... Bottom line is, you don't need experience to be great in bed: it's within you, and you either have it or you don't. Looking for 'technique' advice is the worst thing you could do... Try to feel what your partner feels, sense how he responds to what you do... Great sex is about one thing: being there!
You're obviously into sex, and if you masturbate frequently, you apparently like it :) That's great!
As far as 'normal'... There isn't such a thing as 'normal' when it comes to sex. There is vanilla/kinky; boring/great sex.
Great sex is when you feel alive, when you feel yourself - and make your partner feel that way. Men love a girl that makes them feel alive, esp. older men. The reality is, most people go through life having boring sex (most girls are passive...), so when a man is with someone who's letting go completely, they love it.
When you have sex, you're expressing this part of your personality that can be completely different from who you are in life... Mainly, you should have fun. Chase him, show him you're in control - you want him to reveal his inner beast. Sex is carnal, it's all about raw sensations :)
What is realistic for a first time depends on your state of mind, if you trust your partner, if you're turned on by him, if you've fantasised about it... And your body.
I find that the best way to completely let go is to be with someone you trust, whether it's the first one or not. Lame sex is when you don't really want it, whether as a man or a woman.
As a virgin, taking your time isn't about 'making sure he's the one' at all, it's about making sure your partner isn't a jerk who won't appreciate you and, worse, badmouth you. As an experienced person, it's more about 'do we have chemistry'.
You should definitely be excited about it and not do it because you're 20 and clock is ticking. Nothing wrong with not saying you're a virgin. Also, you should make sure your partner matches your (sexual!) personality: he may be a great friend but not be as kinky as you are, or too freakish for you. Trust your instincts on that one - if you're not having fun when you're left alone, if it's boring, move on. You don't owe anyone anything: it's your body.
Something else I didn't expect: I didn't bleed or have pain my first time at all. I was extremely turned on and well lubricated. Still am. I have never needed lubricants, and I am not a fountain girl and super tight. You want to keep yourself tight: never stretch your pussy. It doesn't feel good to men.Bodies are different :)
On the bigger and better issue - I'm definitely not into too big. I can take it, but I don't like it. What matters most is firmness!
One last tip - DIET matters. If you can feel how a guy feels inside you, trust me, they can feel how you feel too. Same thing with taste. If you finger yourself, you have a pretty good idea of how you feel. Perhaps have you noticed changes and been able to associate it what the food you eat. If not, start paying attention.
'Good' pussy is silky pussy: you get natural lubrication, it feels like you're caressing silk. Your cum taste sweet - it's pretty much the alkaline diet, or a vegeterian diet (eat your greens!).
'Bad' pussy is loose pussy: you feel like a giant hole to the guy who can't feel anything. You taste acidic. That's pretty much junk food.
Also, it's normal to have a little apprehension the first time and question your 'performance'. But trust me, it's only a big deal because people make it such. Just trust your instinct.