Help me Im gonna turn into the 40 year old virgin!!?

Help im 27 and a virgin i have a medium small and have never had a girlfriend all ive done is gone to strip clubs. I have kissed a girl french kiss once but that's it. its like i have had about 4 chances in my life to either get laid or ********. One was so deliberate the girl asked me to her house cause he parents were gone. Ive always been to self conscious and have some mild problems. If I was good in bed and knew it i would have m confidence and would have had by now what do i do its getting to late. When i was in high school i was a pot head and smoked tobacco so my drive was dead all through high school. But i quit when I was 19 and from then ive had the desire but still am not very good problems. Im to embarred i wont perform so i avoid it even though I have had opportunities Because of this i am a loser who often feels like killing himself so please help with some comments.