Tankless Water Heater Q?

I am thinking of putting in a tankless water heater. Our water heater is old and not always consistent. I see the Home Depot has a 27kW and 5.3GPM heater at a great price with good reviews. My wife takes a bath and I take a shower typically once a day*, but we have a little boy on the way (not really going to be a problem, if any, for quite a few years). We don't bathe at the same time. I wash dishes (by hand) once a day for lunch.

*sometimes twice.

Typically, is 5.3GPM sufficient for my needs?