45 is just about optimum for starting out, and, for the most part, carrying on. It's legal for most game in most places. If someday you draw a moose tag or go after elk, you can build up from there, but starting off any heavier (or making too big a jump, if you've been shooting your wife's 35) is usually an invite to bad shooting habits.
I had a guy come down for coaching last week. Moose of a guy, but hadn't shot trad before. He'd equipped himself with a 50 longbow and a 55 recurve and figured he needed form help because he couldn't hit anything. I took him out back and gave him a 40# Hill and ran him through an aiming drill. Right off he started hitting pretty darn well. Wasn't anything wrong with his form if he was using a bow he could handle. He ended up taking one of mine home with him. Once he has shooting down pat and convinces himself he's a good shot, he'll be able to work up in weight.
Starting off with bad habits and ingraining them can take you a lifetime to get over.