This is a tough call figuring infielders and outfielders have a different range of lengths that their gloves are "supposed" to be.
Infielders: 10.5" to 11.5"
Outfielders: 12" to 12.5"
In my opinion I would look for an 11.5" glove. Although it is only a 1/2 inch, it makes a big difference when playing third. When charging bunts, fielding grounders, etc. it makes it easier to take the ball out with a shorter glove. These situations happen a lot. In the outfield all it means to have a glove 1/2 inch shorter is that if you make a diving attempt at a ball you could miss by 1/2 inch. So, in my opinion it would be smarter to go for a 11.5 incher.
Of course, if you have an idea which position you would like to pursue more as you progress, I would buy a glove that suits that position instead of both positions. Gloves can be expensive, so you don't want to buy a 12.5" glove if you really want to play 3rd base. Another option is to go to a used sports store and buy two used gloves one 12" for outfield and one 11" or 11.5" for 3rd.
Cheers!
