Had sex for the first time, couldn't climax. (Male)

I'm 18 years old and just had sex for the first time last night.

It was with a girl I've known for a year now and we're really good friends.

We did a lot of foreplay, but neither during oral or intercourse could I come.

Don't get me wrong, it felt amazing, I can't think of anything more exhilerating than what we did that night - but I was just so disappointed (and slightly embarassed) that I didn't climax.

The whole affair lasted a good hour and a half. A ton of foreplay, I was hard during all of it, but when she went in for oral it felt great and she was really going at it, but I couldn't come. Now here's the really weird part, when she asked to have sex (side note, we didn't use a condom but she told me she was on the pill and was clean), so I mean that considered, sex with no condom, and it being my first time, I should have stereotypically lasted seconds - but I didn't it was a good five minutes of that, we moved on, did a lot more, and came back to it and I still couldn't. I even tried pulling out and finishing myself but that was also impossible.

I masturbate on a regular basis and did the night before, that on top of me being incredibly nervous - could that have been my problem? I mean it sounds easy enough to say it is, but I'm afraid it might be something else.