Hi there Jdhillon1,
You've already gotten some good advice here, but I'll chime in with my .02.
You have a baby on the way, and as you know babies are expensive to raise. This is assuming everything goes perfectly. In less ideal scenarios (medical issues) then it's more expensive (but wait you're in Canada so this may not have the impact it would for many Americans). I recommend you keep everything very frugal for now as you grow your business. Keep everything stable with minimal changes as you welcome your new bundle of joy and grow your business. Save up for a much bigger down payment, even if you can get low interest financing for 84 months. I'd put at least 10k down on an M3, possibly 20k if you can swing it.
I'm about to buy one in a couple months too, but I'm just waiting on some things that have to happen first (like I've waited for a couple years). So, deferring your dreams is part of living, but the main thing is you will avoid chaos if you're met with unexpected costs. With a new baby, even the expected costs will be quite high until you're used to your new normal. Good luck growing that business too!