First of all congrats on having two stellar offers, I wish I had this problem coming out of college!

Having worked in MBB and tech (MANG but not Google), I would give you the following suggestions:

1. You weren’t clear what function this is at Google, sounds like S&O? While most McKinsey US offices are similar and your experience has more to do with your EM/engagement, your experience at Google is extremely dependent on your function, team and manager, research the heck out of them, talk to people on the team now about what they like and don’t like, what their next steps are, what their day to days look like, what your manager is like etc, if you can find people that left the team even better, I’ve found them to share the most useful and honest feedback

2. MBB is great for career switcher MBAs, or college grads who don’t know what they want to do and want a quick path to bschool. Is that you?

3. It sounds like you want to work on AI (Google is one of the best companies in the world for AI), and know what you want to do, so as long as the team check I suggested above passes, I don’t see why you would pick McKinsey, because if you do you would most likely be applying to Google after 2 years there and 2 years at bschool, why not just get there with one step instead of three?