I am going to buy my first walk behind mower next week and have only one concern? Should i get a 36" or 48" fixed deck EXMARK -Metro gear drive?What is the biggest difference?This will be my first and only primary mower to get started. (I may get a 21" to trim )I do not have any yards with gates, and no yards are that big. some have trees and stuff that i am scared will be hard to go around with the 48". My question with the 36" is yes it will be easier to go around cust. yards, but if i do get a larger yard to cut will i have to turn it down due to the mower being too small? HELP!!!! Is there any recomindation on what is the maximum size yard to cut with a 36" or 48". Has anyone found the 48" to be too big for small to medum residential yards. THANKS for any input!!!!!