With your size and fitness level, you should be able to work into the heavier weights without any problem. But, only if you need to or want to.
PLenty of deer sized critters end up on the dinner plate at the hands of 40-45# bows. Fred Bear built 90% of his bows in that range.
A good friend once asked me " How far do you want the arrow to go after it goes out the other side of the deer?".
That being said, my first longbow is 57#@ 28". Before I ordered that one, I worked through a range of recurves from 40-50# . I love that bow, and shoot it often. My 2nd longbow I ordered 52#@27". All in all a little lighter than #1. broke it in with a 7pt buck this past fall.
My wifes longbow is 41#@28". I shoot it a lot for form practice. Light wieght, comfortable as all get out to shoot. I am definitely more accurate with it, and I I use it to focus on form, then when I shoot my heavier bows, my form is better and I shoot them better. If I feel bad habits forming, I immediately go back to the lighter bow to resolve them.
A couple months before huntin season, I decide which bow I'm gonna hunt with, and that is the only bow I shoot till the season ends. I can tell you 45# is too light for elk in my opinion. . They are thick skinned, thick haired and big boned. I've seen elk killed with 52#, with a heavy arrow and a close shot. no 35 yds shots with that setup.
Since you are getting a 3 pc takedown then I agree with what some of the others say, go lighter to start, then order a heavier set of limbs later if thats an option for you. At my draw length, both my bows are 50-53#. Plenty for me,and with arrows pushing 600gr, penetration is not a problem.(unless you hit an elk shoulder. But then they stop everything)
I think you'll find a vast majority of trad archers have bows in a range of weights.. Or at least started out that way. Good luck and good shooting to you.