The stuff I hunt you need a fast arrow and most of the time thier not in that magic 10-15 yards.
like my bows in at least 55# to 70#  My arrows are about 400grns.

It is your journey, what ever feels right for you. I used 67# @ 32" HH Wesley with much success for many years but degenerating discs and joints forced me to lower poundage to 50# @ 32" for any consistent shooting. I can still draw the HH but after 6 or more shots wow can not handle her. I am 6' 4 & 3/4" just had to come up with funds selling a Redman and a few guns to get the new tools at the lower #'s.

I'm 68 and have been shooting bows from 43-50# all my life. I can shoot 55# if I had to but no reason to. I'm shooting the 45# for 3-D and 50# for hunting. Right now I'm recuperating from elbow surgery so not shooting anything right now.

It all depends on what you want from archery.  At your age there is no way I would limit myself to 45# if I was intending to hunt for the rest of my life.  You may only be hunting whitetails now, but some time in your life you may have the opportunity to go after something bigger and tougher, and you will need more bow weight.

I'm almost 68 years old, 5'7", 154 lbs.  My favorite bow is 55# at my 26 1/2 in. draw, and I don't see myself dropping more than a couple of pounds over the next 10 years.  If you keep fit, do some toning exercises and stretches as you get older and continue to shoot your bows using good form and correct alignment there should be no reason to have fears about injuries from shooting a bow heavier than 45#.

Maybe a 45# bow is entirely adequate for most big game hunting, but with my meager 26 1/2" draw I feel that I need the extra cushion of an additional 8 to 10 pounds of draw weight - besides, I shoot 53-55# bows better than I do 45-48#.