you're only 13. Your seminal vesicles might not be up an running fully yet. Give it time. As long as you don't feel pain, discomfort, or have blood in your ejaculate, you're fine.

I jacked off every day too and lots of time it was clearish. Its probably no problem at all. When I got married, my wife got pregnant right away. You can jack off as much as you want it cant hurt you. but you should listen to whatever others say too. I only say this from my personal experince. Good luck.