You need to be absolutely, positively, 100% sure that you won't have to pay for childcare to even consider this plan--with chld #1 and any other kids you might have.
We have a $500k mortgage at 3.5% (monthly PMI of about $3100) and an income of $250K and this allows us to live a comfortable lifestyle-- rent a summer beach house, eat out on occasion, pay for preschool, save for retirement, save some for college, buy clothing as needed at places like the Gap/Jcrew (on sale), etc. A very nice lifetstyle where we never worry about money-day-to-day but we have to budget for larger purchases like new furniture. On $160K and a mortgage of that size you'll probably be spending what you make each month. Kids are expensive--even with free childcare.
I think the best advice is to figure out how much exactly your mortgage will be and live a few months with that amount set aside each month (if it's greater than your current rent). AND make sure to check and double check about the childcare for kid #1 and beyond. That will completely change everything because it can be thousands per month.