Just a little advice...all the other people have covered most of what i have to say. i'm 15 and I made out for the first time about a year and a half ago. the only thing i can say, is when you do it, do everything in slow motion. from the moment that you first look in her eyes and you feel that this will be it...take like 10 seconds and just do everything real slow....girls love that.
You said something about havin a mental block...I have a gf now who had never dated anyone before. I had dated 4 girls before her so i took it real slow...well when it came time for our first kiss, i went in, turned my head slightly and about a centameter before we kissed, she started cracking up....see...she's 15 too and she said 'i'm too old to be havin my first kiss...we laughed for like 5 mins streight. dude, we tried like 20 more times to kiss and every time that we had calmed down and were goin in for the kiss...we would start cracking up. finally, at the end of the night after about half an hour of this, we finally got it to work. she just had a little mental block because she had never kissed a guy and i had gotten to 2nd base with a girl before. so mental blocks are normal...it ends up that my gf is having one on frrnch kissing right now...same as you...my advice...every thing has a time to happen...
~David
PS-tell me how it went- AOL sn = freshguitarluvr