Well, when you're old enough, and you find the right person for yourself, sex can/will be amazing! It's a mutual expression of the love you have for each other, and its wonderful with the right person.
Sex is generally a pleasurable experience, which makes people feel happy and connected to the person they are having sex with. Although, it can be a bit more complex than that, as I'll explore below.
It's difficult to describe what it feels like as it's different for everyone, and their isn't really an easy comparison!
However, sex is only enjoyable to both parties if they both truly wish to be so intimate with the other person. They must be both mentally and physically prepared for the experience to feel enjoyable. It is also often said that the experience is more pleasurable when shared between people who love or care deeply for each other.
If you are not emotionally or physically prepared then it is unlikely that the experience will feel good, and so it is best not to have sex merely out of curiosity or pressure. Stress or anxiety about the occasion can also have a negative impact on the way sex feels.
I have no idea.