I'm 16 and I don't orgasm or ejaculate during masturbation.

I am 16 years old. I masturbate once (sometimes twice or more) every night, and I have been for a very long time. I do so by laying on my back or sitting up, and stroking up and down. I get a really good feeling the whole way through, but it never seems to increase in any way, no matter how long my session is. Also, I don't experience any semen at all. I do, however, experience a slight but steady release of clear, slippery "pre-cum". I believe i'm somewhat well into puberty (bush-like pubic hair, cracky voice, stubbish facial hair, and mild armpit hair). Should I be worried, or am I just a late bloomer?