Length of practice ╪ great musician
What you practice matters. +100 on getting a good bass instructor.
There's theory, standard notation, sight reading, ear training, scales along with learning tunes, riffs, etc. Here's one method of practice that may help:
http://www.joesolomonbassworkshop.com/article.htm
Playing in a band/jamming(and recording your performances) is probably the best way to test what you've learned. Otherwise you may become a "legend in your own mind if you stay in your room"!
Since you're so new to the whole music thing, planning such long practices is counter productive. Music is to be enjoyed; even practicing should not tax you physically or mentally. Rehearsing with a band helps a lot.
Since learning is a life-long process, playing steady for 30 years will be better than getting burned out after a year or two. It's not a race.
The better you define your goals, the more focused your practice will become.
Good luck.
P.S. You might want to check out the links in my sig. below for some excellent TB bass info that may help you along the way.
P.P.S Let us know how it's going. Check back in every month.