Good info from cncfish, so true about access to the bow, especially for a first-timer!
You are going to hear a ton of people recommend that a bigger boat is always better. In some cases yes, in others it just isn't so. Things like storage, the place you will use it most and ability to captain the boat all come into play when deciding how much boat to get. We ended up with a 16.5' fish/ski set-up that has been great.
We were in a similar situtiaon as you earlier this year. We made the call to get our first boat, have two little kids that will be with us almost always when we are on the water and wanted something that was "all-around" in nature. Here are the things we decided were not negotiable:
Aluminum hull: Neither of us have experience running a boat, aluminum is more forgiving when it comes to beaching and approaching the dock too fast

Deep-v hull: The wife and kids are with me almost always, a smoother, drier ride is paramount for us. We didn't/don't need a boat that will run small rivers and weren't getting a jet
Weight: The boat has to trailer-able and not just by a 3/4-ton diesel. I have a Tacoma and plan on running to EWa to fish the big rivers and reservoirs over there, a 2,000 lb hull just wasn't going to work. We also wanted to be nimble and be able to run to any of the local PS lakes to dump in the boat
Top: Some sort of canvas-system for keeping the kids out of the sun is a must. I am sure it will be nice for rain when I am out fishing, but we haven't experienced that yet, only used it for shade
Ability to pull skier/tube: We ended up with a fish/ski boat that has a spot for a ski pole, haven't used it yet, but is s pretty slick set-up
Of course there are a ton of other things to consider, but for us during the purchase of our first family craft, the above were the most important for us. Good luck on your search, you won't regret it once you pull the trigger.