I am the same age as you "lookahead" and also experienced the same lack of endurance that you are encountering now. I lost my virginity to my girlfriend last april; about a year ago (who also lost her virginity to me). The first few times we made love we used a condom. I was confident and proud of myself after the first few times because I was lasting longer than 10 minutes. I was self concious going into it because I heard many stories of men lasting between 30seconds up to 3 minutes. Anyways....
She went on the pill and we then started to make love without any protection on me. This is where my confidence left me. I was no longer able to hold it in longer than 2 minutes or so. We made love many times a week, often up to 4 or 5 times in one week. Each time was a disaster for me however. This went on all throughout last summer, and continued into this past fall. It was over thanksgiving break that I decided to look into this problem. I started eating better food (which some people could portray as an urban legend), working out (which I had not done since previous spring). Also, when I would masturbate, I would practice holding it in when it came time to ejaculation. I would stop stroking (excuse my lack of a better word) and pull down on my testicles (which I also heard helps "close" a vessel/tube that transports semen) to help hold back my ejaculation. I would do this repetitively in one masturbation. When it came time to having sex with my girlfriend, I would do the stop and wait method. When I felt the urge, I would pull out, calm down, and then continue when I could control myself again. Often times the urge got the better of me, and I did not want to pull out because it felt so good, but you know what I mean. Also, I would have her pull down on my testicles at this point. Not hard, but enough pressure to help calm my urge. Anyways....
Now, after about 3 months of working on it, I can last about 8 minutes non-stop. Not nearly my ideal time, but it's getting up there, and i'm able to pleasure my girlfriend more and more.
Also if you are capable of it...Do something that I like to call "chain doing it". When you bust, just continue to have sex, and do not lose your erection. Your next ejaculation will not come for a long time, and this can help make up your lack of endurance. It's hard to master, but all-night-long sex will make her come back to you for more.
Don't talk to friends about it, you'll just embarrass yourself. It's better that you came here, where other men of your age, and older, come to recieve help on similar / other problems.
Good luck man, sorry that I wrote too much, I just know how you feel.
Don't do kegal exercises!