Sealing the tile grout -shower area
 

Hello all...
I recently had my bathroom renovated and my contractor did not seal
the grout in my bathroom. It's been a couple of weeks now and I'm
noticing that the grout by the seams (where the wall meets the tub)
looks like it's wearing away. A few people have suggested to me that
I "seal the grout" to prolong its life.
I've been reading up on doing it myself and I have a few questions:
-Do I need to caulk this area (where the wall meets the tub)?
-How long will the grout sealant need to dry/cure/etc?
Are there any other suggestions/comments anyone can provide as taking
care of my shiny new tile?
Note: This is glazed ceramic tile so I was told that the tile itself
doesn't need to be sealed.
Thanks in advance for any input.
Lisa