Teenagers are described as "Curious pre-adults". They do things out of curiosity. They often think they are ready for something when they aren't. We all do this. I suppose it's just what we do. They want to see what it would be like if they were dating someone. They would know if they were ready, what gender they like, (I mean, you can learn if you're straight, gay, lesbian, Bisexual, Pansexual, etc. At a young age, but there is a chance you can find out as a teen.) And when they could start at.
Hope you find this helpful!