There's no semen after my first self stimulation

Hi I.s.s

There is nothing to do you may have just not reached the point in your development that you are able to ejaculate.

Since this was your first time masturbating there is also a chance you didn’t do it long enough.

Was there any pre-cum during masturbating like a clear sticky liquid?

When you started puberty and how far you are into it could also be why there was no sperm.

Thank your lucky stars for the dry years when you can masturbate as much as you want without it being messy. It will get really messy soon enough and then you will have to use something to catch it in. While it's still dry you or your girl can do it inside your pants with no tell tale wet spots.