That is so common. My daughter even hates to say things like, "When me and my friend go to such and such a place in July" because she always thinks, "Oh no, I may not even be here in July!"
I also had an older friend who swore she'd never make it to 30, around 32 she swore she'd never make 40, then swore she'd never EVER make 50... she's now almost 60.
My mom said that when she was a teenager and would hear church bells ringing in the distance that she would have a panic attack thinking it was a "sign" that she was going to die in a few days! (she's going to be 79)
Common fear for anxiety sufferers.
You are messing with your own head there.