To be or might be

This is yet another question that's been bugging me (occassionally) for the past few years.

I've noticed for quite a while now that I seem to navigate myself with a back-up plan to fall back on at all time. Well,... at least most of the time.
I'm not sure when this habit started, but it's definitely been going on since I was much younger.

There's always this statement going on in my head:
If this doesn't work out, I'll go and do that instead.
If I don't get accepted here, I'll still have that school to go to.
If I can't find a job in this field, I'll try to go for that field.
If I can't stay here, then I'll go there instead.

Maybe it's due to my mom's influence on me. I guess one can say that I was fully trained in worst case scenarios by her. Among other things, to be prepared for the worst seems to be one of the critical points she's instilled on me since a young age.

But now I wonder if having all these back-up plans is actually a distraction in my effort to achieve whatever goals I might have. I wonder if my ex-boss was correct when she told me that I had the persistence that some people didn't. You see, I know some people who are very adamant about what they want. It's always a case of "to be or not to be" and not "to be or might be" for them.
I think this helps them to be very persistent and more consistent in what they do.

I must say, it's a really tough habit to change though. I don't think I'll be able to get a good night's sleep without any plan-B.