I actually received that exact kit when I got my BP for Christmas. He is 6 years old and about 3 ft long, but I upgraded to a 40 gallon breeder tank, which will be his tank forever. I think it is big enough to hold a bp, except for big females, for up to 5 years. I got my 40b because I found it on craigslist for 20 dollars and new he would eventually need a new tank. As for the other stuff in the kit:

The mist- SMELLS BAD, VERY BAD!!
The bowl- tupperware containers are better- a baby bp could barely soak in that one
The reptile carpet- I think newspaper and aspen is better
The rock hide- The only thing literally that I am still using- its a pretty good hide

So all in all I wouldn't recommend buying it- and I do speak from experience