RE: new runner - how long should it take me to run 5k? (1) For a new runner, I think a good goal would be to average under 7 minutes per mile for a 5k. 6:59 pace x 3.1 miles = 21:39. (2) After that I'd imagine 20:00 is a nice barrier. To run 19:59 you'd need to average 6:26's. (3) 18:59 - now you're starting to get a little more serious.
OP, usually when you see the term 'fitted shirts' or 'shirts in fitted sizes', that means neck and sleeve measurements describe the shirt's size. Note that users of MFA may use the term differently..... Also note that even if you buy a shirt in fitted sizes, you still probably will have to have it tailored!
For a man it tends to mean decent dress shoes, slacks, and a button-up collared shirt tucked in with a belt. Tie optional. I could be wrong. Still, I would avoid flippy-floppies, shorts, and that old Megadeth band tee.