Hi wings,
You need to look at the requirements for the medical schools you are applying to, and make sure that those courses are a)current (they usually list a time frame) and b) eligible for consideration.
You can do it with kids, especially if they are school-age when you start, but I wouldn't count on working. It's a bonus if you can, but don't count on it. You should schedule your MCAT around the cycle you would like to apply to as well.
I don't think you're too old at 34, but you should prepare yourself for a large debt load at the end, long hours for about a decade to come, and less stamina than your peers that will be 10 years younger than you. This doesn't apply to everyone, but these are issues that non-traditional students do face. I think with your academic background you will be fine, though.
Another big component is how your spouse feels about this. It's important to have a strong supportive network when undertaking a life change like this when you have a family.
Good luck with your decision, and I'm sure others here will have more to offer wrt advice.
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"Some of it's magic and some of it's tragic but I had a good life all the way."
- He Went to Paris by Jimmy Buffett