Take care of yourself, by not making a major social, family and societal error, you just sidestepped a big problem. Girls your own age are lovely, too.
AnnieBrook and specialmom, thank you really. I think I get it now thanks to you and some others. I understand now and completely agree with you both. It's just a stage and it will pass. All I have to do is focus on life and my tasks and probably forget about it. Maybe I'll try and find some girl my age as you recommended. Thanks from the bottom of my heart and I truly appreciate it.
Yes, I agree. Keep the fantasy to yourself. These things usually pass. You are at the raging hormone stage of life without a lot of outlets. This usually gets better. In many parts of the world, it is quite taboo to have romantic relationships with your family. And it would be very odd for a 20 year old young woman to be overly interested in a 16 year old boy. :>) So, get really busy with life, school and kids your own age. That's my best recommendation to you. I have a 16 year old son. I'm here to tell you that the next few years begin the shaping of your future. Your school work and extracurricular activities are important! So, try to keep your focus. I know, that is very mom like of me. But realistically speaking, it's fine to have thoughts in your head. But telling her or trying to act on them can create a lot of either difficulty or awkwardness for you in your family.
No, do not tell her. Just about all a 16-year-old consists of, is hormones. Your attraction is pretty much just biological, focusing as it does on her body parts. Telling her would be no compliment, she would probably be very appalled. Word might even get around the family, and they would REALLY be appalled.
Men and women are different about sex. To put it in an exaggerated way, pretty much any men would be glad to have sex all the time, and hardly cares who it's with. But because of this constant level of demand, women are disinterested in being treated as only bodies who are supposed to be happy to satisfy men's lust. If a woman were to say to a man "I like your as* and think about having sex with you," he would be delighted. If a man said it to a woman, she would be irritated, because that is what every man says. Finding someone who would love and care for her (whether or not she has a caboose and boobs) and would be pleased to be able to stick around and help her raise their children, is her problem. The last thing your cousin needs is yet another horndog in her life who thinks it is a compliment to tell her that he is lusting after her, especially if that horndog is her teenage cousin.
Fantasize if you must, or even better, find a real girlfriend you can care about. Good luck!