Glad I’m not a tiger parent:) Michigan is my alma mater and one of the schools that accepted my son. We were over the top excited even though he was only a Wolverine for about an hour.
The worst offense, IMO, is when parents post on FB: "Junior got into Harvard!! All that hard work FINALLY paid off!!
As if it was just a matter of hard work and other students didn’t work hard enough.
I feel guilty when I’ve done something wrong (or eaten too much pizza).
Your kid getting in to where he wanted to get in to is nothing to feel guilty about! It’s awesome!
However, being mindful of and sensitive to disappointed kids out there kinda goes without saying.
I asked the girls if they wanted me to put college stickers on the back of my car when they go to college and the younger one said no, because if it was an elite school it would feel like bragging, and if it was a normal school then who cares? 
Older one said she didn’t care what was on people’s cars and didn’t care where people went as long as they were happy.
Nothing to brag about. This is really sad that kids would be abused into thinking that Michigan is not good enough.
Try to enjoy the good fortune while home, but be low key elsewhere. Fear not… in a few months you will be distracted over making the final decision. Good luck!
My daughter didn’t tell anyone. For months. Even when the subject came up. My son told faculty and friends on the first day. This is the start of many years of low keying if it is an elite school. Sometimes I don’t know why everyone wants to go to Harvard et al, since you have to spend the rest of your life hiding it with many people : )