Before details, homosexuality is a same sex attraction. Now, details. Putting aside all the bits and pieces, think for a minute. You have a choice of who you wish to cuddle with as you sleep. Would that be a male human, a female human, or so far you prefer a pet or sleeping alone and don't know yet? One day in the future you may wish to live with a life partner, to share your life, maybe raise a family, someone to be your partner in life. Do you see yourself with someone of the same gender, or more commonly the opposite gender? Does your heart race and imagination flow in sexual fantasy in a partner of the same gender, or the other?
It's not about how you imagine yourself, but rather who you want to be with and love as a friend and partner in life. It is a good thing if you allow other people to make their own choices and you make your choices.
In your mid-teens you may know now, or not be sure, or want to explore. Everything is normal because your hormones are raging and you're curious. Don't make a girl pregnant and learn about sex. If no one is teaching you, do your own research. Learn about sexually transmitted diseases and the necessary precautions. You'll figure out your own desires over time. You're probably straight (heterosexual), but may be curious about some things.