The more money you can put down on a house the better. As to first time buyers....they need to stick to their budget and not try to buy a house like mom and dad have and find themselves in over their heads. The current generation wants it all right now. They don't understand starting at the bottom with a starter home and working their way up to the dream home. Typically as you get older your wages increase and you can afford a bigger house. They forget to take into consideration that even though they may qualify for this house that things are going to pop up that they may not expect and may make it so they can't afford the mortgage down the road. For instance, increasing taxes, increasing home owner's insurance rates, plumbing problems, electrical problems, a new roof every 10 years or so, appliances that break down, water heaters that stop working, wells that stop working, job layoffs, death, pregnancy, illness , etc. IF they can afford the mortgage and put aside money (at least $5000-$10,000) in case these things happen then they should be ok. But most people don't and find out the hard way and end up in way over their heads and in foreclosure because they don't think about those things.
I'm a Realtor.