If you look at the UMich CDS (Common Data Set), the two most important factors in their admissions decision are uwGPA and course rigor, which is what @Knowsstuff mentions above.
Also, as @Knowsstuff mentions, I think your best case scenario is a deferral in EA. And then, UMich will probably want your 1st semester senior year grades. So, keep your foot on the gas pedal and do really well. 
It’ll be an odd admissions cycle this coming “season,” so you just never know. I keep telling my '21 kid to expect the unexpected. :grimace:
The OOS acceptance rate is 19% and the middle 50% for the entire admitted class is an uwGPA of 3.9 and an SAT score between 1,380-1,540. OOS students tend to be on the higher end of the class range.
If accepted to LSA, but not Ross BBA, then you have a couple options in terms of Ross Business School. You can apply to transfer to Ross from LSA, but the cross school acceptance rate is 51%. The other option is that Ross offers a minor degree in business.