Here's my advice and remember it's usually worth what you pay for it.
Also, not trying to lecture, but share my experiences as a Medicare eligible person who has not had a mortgage for over five years.
Put down the smallest amount possible to get into the house that you can if you have high confidence you can make the payments.
This does a numbers of things:
1) Keeps cash available if you need it for home repairs, remodels, life emergencies, etc.
2) You are paying back the mortgage with lower valued dollars. Inflation, and our debt based economy, is going nowhere anytime soon so why not pay them back with dollars that are losing 5-10% of its value every year? Just be sure you can make the monthly payment.
3) If housing prices crater like they did 2008, then a "strategic default" is a viable option which means you'll lose little since you put a small amount down. You put 20% down and that disappears in a SD scenario but a 3% or 5% DP loss is an easier pill to swallow.
4) If you home appreciates in value never, ever use it as an ATM unless somebody's life is at risk.
20-30 years ago I was of the mindset that you sign a contract like a mortgage, then by god you make the payments no matter what but the last 15-20 years has opened my eyes to do what's in the best interest of you and your family. Corporate America got a free pass for bad decisions of biblical proportions so why not you or me?
Good luck,