I am an older med student, currently 39, wondering the same thing. Any of the surgery residents I talk to think I am absolutely crazy for even thinking about it. One told me the difference between what is a hard day for him and what is a hard day for a medicine resident is like night and day.
Howver, I have no pressing family obligations. I also go to a school where any medical student can pretty much go to the major Level 1 tramua center at any time and jump in on whatever they want. So, though I have yet to begin my second year, I have already scrubbed in on several surgical cases. There is nothing like it.
I wonder why you are specifically focusing on competitive surgery programs. Realize that many of the big name programs also have a plethora of fellows in various surgical subs. In such an environment, residents may not get to do as much as they do at a lesser known program. What makes you a good surgeon is not the name of your residency program, but how good you are doing surgery...something that only comes with practice. You can't practice if the fellows are doing all the operating!
Just keep an open mind. A lot can happen between now and time for you to match.