Most Helpful Guy
It's normal. You see something you want so you feel threatened when others look like they may take it from you. It's in your DNA from millions of years of evolution.
So feel free to feel jealous. It doesn't make you a bad person. But also try to work up the courage to do something small everyday to try and break out of your shyness shell. You can do it. I was once very shy when I was in my early teens and younger but consciously made an effort to reverse that and it worked.