First off: Welcome to Chief Delphi and FIRST.
Don't feel dumb about anything here, we were all new here once and this is a place of great information ... all you have to do is ask.
As far as how many matches you'll get, the above posts are correct.
You'll have 2-4 practice matches (these don't count).
You'll get 7-9 seeding matches (These DO count).
If you get into the elimination matches,you'll have up to 9 of those.
Don't forget to explain to other teams what your robot can do, sometimes even if you are not placed well (during the seeding matches) your robot may be exactly what another team is looking for to compliment their robot.