Hun, you have been abused, and whether you realise this on a conscious level or not, there will have been emotional consequences. You were introduced to sexual things at a very young age, before you were emotionally and psychologically mature enough to process anything. As you were so young, you were in a situation of physical, emotional and psychological danger. A child is not capable of making informed consent, and an adult who abuses this is a predator, with deep psychological problems.
You really need to talk about your feelings with a professional, who can help you to process them, and find a sense of healing. This is very important.
Now that you are in puberty, your body is going through changes. Having sexual feelings at this age is normal, and so is masturbation. However, it is illegal in many parts of the world to indulge in sexual intercourse at this age, and the law exists for a reason. Although you are physically mature in many ways, you haven't caught up in terms of emotional maturity, even if it seems to you that you have. Your brain won't stop developing for some time. Having a sexual relationship contains a risk of pregnancy, an STD, and also the risk of being physically attacked by a partner or being forced or co erced into doing things that you don't want to do. It carries with it a lot of complex emotional implications. Many older men will exploit, using flattery and praise to get a younger person to comply to what they want to do. They could lead them into situations where they are in danger, and there is a high chance of this. Very often this is subtle and not overtly obvious. These issues are too much for a person of your age to cope with. It's safe and harmless to keep your fantasies in your head, and to have crushes on people, but to act them out and seek men out on the internet in this way is putting you at risk. It's opening you up to more abuse, hun, and it's putting you in danger.
Older men in their twenties, thirties and older are not naive. They have life experience. They have little in common with someone of your age. Although they may look at someone, not knowing that they're underage, they would be horrified to find that they'd been tricked into sleeping with someone or engaging in sexual activity with someone because she lied about her age. This revulsion and horror at the realisation is a normal reaction. The men who would do this, and who make a point of seeking younger people out, engaging with them on the net whilst being aware of their age, are paedophiles and their motives are not good. They are capable of great harm that you couldn't even imagine. For your own safety, you must stop seeking them out on the internet, and perhaps tell the police or get an adult you trust to do this. This would prevent them from harming any more people.