I know this is a rubbish thing for me to say but you're only 16! You know, most of my friends didn't have boyfriends throughout highschool and now at least 3 of them, all 19 now, are in relationships. The rest have either experienced one or are just waiting, as you are! Worrying about being single when you're much, much older is so frivolous right now. You needn't worry. And hey, as for people never getting married at 42 or whatever... my uncle (he's over 45), as of last year, is in a completely stable and extremely happy relationships. It happens! You're still incredibly young and I have no doubts that you'll meet someone along your way. You have the rest of highschool to go, college if you choose and whatever jobs you have in the future. These things all provide you with the chance of meeting people. Keep your eyes open and if you see someone you like you have to take that chance and make a go of it, don't you think?
Try not to worry too much about that part of the future. Relationships just fall into place and meeting the right person can take absolutely forever and some patience. I understand it can be pretty depressing to be single when you really want to be in a relationship, especially if the people around you are comfortable with someone too. It can feel pretty lonely. Think of it this way though, you've got like... another 70 years or something on this earth. You honestly think you won't meet one single guy who you like and who likes you back? I would think the odds are in your favour :) This kind of stuff is difficult and I suppose a little bit of fear is ok. We all experience that when we think about our futures. Take it as it comes though, and grab those opportunities when they arise.
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i think you're the same as me, we see things they'll never see