In my opinion it would be much better to get a lighter weight bow. You may very well be able to build up to the heavier bow, but in the process it's very easy to develop bad habits, you won't be able to shoot as many arrows, you won't develop your accuracy as quickly, and you won't enjoy it nearly as much. Probably 40-45# max. is what I'd go with, or lighter.

Physical size, or even condition, doesn't always matter--usually it doesn't matter much, if at all. I've seen little guys pull heavy bows easily, and big guys struggle with lighter bows. The reason seems to be that the muscles we use for archery aren't normally used much by most folks, so they have be be built up. Even a compound pulling 70# won't exercise them much, because you only hit that peak weight for a split second and well before you hit anchor and get stretched out.

For the sake of being easy on my math skills, say you shot a 100# compound with 80% let-off--you are only holding 20# at full draw. I helped a friend at his shop back whenhigh let-off compounds were introduced--we scaled it, and I think on a 70# bow the holding weight was less than 15#. If memory serves me right, it was a McPherson with either 80 or 88% let-off--it was the most let-off of any bow at the time.

You'll be doing yourself a big favor, and improve much faster, by going a lot lighter. Besides, 40# will do the job on most game animals in North America.

Chad