I am going to say that it's because he is too young. At his age I hadn't even considered the option seriously. Try an older guy or wait for your man to get older and more adventurous.
Don't worry, just wait, your time will come. My wife refused to even try anal for 5 years. Once I got her to try it she realized how great it feels. She started slamming back into me and moaning like I've never heard her do before. Now she suggests to me that I should fuck her ass at least one time per week. Patience, ImaMuffin, your time will come.
yep, if its not comfortable then dont continue. Personally, i absolutely love anal. We do anal about 90% of the times we make love. I always thought that all guys were desperate to give a girl anal but most of them are really nervous about doing to. I really had to convince my current bf to try it. But ever since the first time, he's loved doing it too. Because we do it lots i'm used to the feelings and i know what to expect so my anus doesnt tense up. Thats the trick, your but needs to be as relaxed as possible. I always need regular sex before going anal. It sort of prepares me and gets me most horny. While your guys pumping you or going down on you, get him to stick a finger in your but. That always gets me going