Switching to Prot (Post 70)Follow

Good morning all. I have decided that I am going to give Prot a whirl and attempt tanking for the first time with my warrior. When I originally rolled him, he was strictly going to be for PvP/Arena only. Now, I am getting the itch to start some tanking and would like some advice. I have did the research on threat rotations and feel comfortable with that. My armory is below (Ogtoo - Alterac Mountain Server):

http://www.wowarmory.com/character-sheet.xml?r=Alterac+Mountains&n=Ogtoo

First question is Defense. I have saved a few tanking quest pieces but do not have nearly what is needed to get 490+ defense (or whatever the # is at 73). How will this low # effect my survivability? It will take me several levels to actually get some good tanking gear. Is it ok to attempt to tank now or would I come across as "newbish'?

Re-gemming Gear - I have enough gold to where it wouldn't be a problem but do you suggest doing this now on my current set? It seems most warriors gem with +12/15 stamina but what would you suggest for future sockets?

Glyphs - What do you suggest for the minor and major glyphs?

Any extra advice will be greatly appreciated. I am really looking forward to trying this out.