Honestly, what you are going through seems actually quite normal. Romance, dating, and sexuality have many different components. There is much room for flexibility.
I am a layperson, not a professional, but I can tell you what I know from my own life:
1. Sometimes, emotion and sexuality work together, sometimes they do not.
I am a heterosexual male. However, when it comes to emotions, I relate better to other men. I have some male friends who I can say "I love you", even though I do not want to sleep with them, etc.
Even if I am romantically involved (with a woman, of course), I often cannot understand what they are trying to tell me, and they do not understand me. If you notice, it is a very common theme in sitcoms: men do not understand women, women do not understand men; all couples of any orientation drive each other nuts, it is just what they do.
2. In many cultures such as Middle Ages Europe, Puritanical America, Islamic culture, Africa etc. homosexuality is criminalized and given a summary death penalty, etc. In other times, such as Greek and Roman Times, it is encouraged.
Whatever the crowd is doing, individuals seem to experiment more with.
3. A lot will happen when you start becoming sexually active.
I actually thought and worried I might be gay, simply because I can recognize other men as being attractive, relate better to them, etc.
But, in my own life, when I started having sex, I basically "knew" ("women are the right people for me to sleep with"). I still relate better to men than women; but, when it comes to sex, I want women and only women.
4. Again, many studies show shades of gray.
In some countries, like Austria, supposedly up to 50% of the women WHO IDENTIFY AS HETEROSEXUAL have actually had sex with another women.
So, even if you do decide to try things with another person of your gender, etc. there is room for shades of gray. I have had girlfriends who are attracted to women, or even try things.
5. So, nothing to feel guilty of or ashamed of. Just keep on going through your life journey and thinking yourself.
So, I'm the mom to a couple of teenagers. One thing I can say that seems to be very universal is that many kids go through a 'soul searching' period. You're trying to start establishing yourself as an adult and what all that means. You're trying to understand who you are and who you will be. You are certainly not alone. And questioning your sexuality is something that many do. I think it will become more and more clear. And there is no wrong or right answer for the outcome. I would try to relax and not force yourself to 'figure it out' right now. I think it can be very normal to question yourself and to feel confused at times. If time goes on and you still feel this way, a therapist can be wonderful to sort things out with. But the 'right' path for you in terms of your sexuality usually starts to lay itself out in undeniable ways as time goes on. These are the years to really become strong internally and that may include doing what builds your confidence and self esteem. Sports you participate in, band, theater, academics, time with friends, working, etc. I hope you see the beauty in having your whole life in front of you as you figure it out. :>) but I know it's a challenging time.
There are all kinds of different ways this could play out - you could be heteroromantic or heteroamorous (liking romantic relationships with both genders) but bisexual (liking sex with both genders) or any variation thereof.
There are romantic orientations and sexual orientations. Some people have the same romantic orientations as sexual orientations, others don't. For some, it's always evolving and changing.
You're 15 - it may be that you know this is what you are, and it may not change. I mean, no one ever tells the straight kids at 15, "well, this is a time of change for you", right? Or it may change. You might change at 45 or 50.
The most important things to remember are that you always have the right to say no, consent is a must, and your feelings are really important. The rest works itself out.
Here's a whole module that seems pretty decent - you can scan through parts that don't interest you - https://www.usd.edu/diversity-and-inclusiveness/office-for-diversity/safe-zone-training/sexual-orientation-versus-romantic-orientation