As far as shallow water diving goes, the best places are coral reefs (like Hawaii), you can spend all day in 30 feet of water and never get bored. The great advantage over snorkeling is that you can get very close to things (like tiny fish that look like designer handbags defending their little patch of coral) and see things in 3D, sea turtles slowly drifting past you, small sharks warming themselves on sunlit patches of sand like cats.
For maximum safety, avoid diving sites that have currents or boat traffic, and shore dives with strong surf, those are probably the biggest risks to a beginner in shallow water. It's also a good idea if diving with your family for the most proficient one or two of you to eventually take a rescue diver course, which will teach you how to help a panicked or incapacitated diver. Good luck and have fun—good safety habits go a long way in this activity, and you are in for years of enjoyment diving together.
Scuba lets you get closer and it's wonderful to feel the true 3D freedom of movement. But in terms of sight seeing snorkels get got 90% of the joy for 1% of the effort.
Bear in mind that the rate of change in pressure is higher at shallow depths. At the surface pressure is 1 atmosphere, it will be 2atm at ~33ft, 3atm at ~66ft and so on. This means that if you have a momentary loss of buoyance control and shoot up, say, 10ft, it is a much larger sudden change in pressure (i.e. more dangerous) to go from 20ft to 10ft than from 100ft to 90ft. So having expert buoyancy control is actually more important at shallower depths.
It just takes practice, but it is a risk for new divers who go in thinking they'll just stay shallow but do so without having mastered boyancy yet.
For shallow dives I use nitrox at 36% oxygen to reduce nitrogen absorption. It's easy to get nitrox certified after completing basic & advanced training so I'd recommend it if shallow diving is a primary goal.
Although at 15ft or less I generally just snorkel if the visibility is any good. At such depths you can see the same by snorkeling, with less risk and hassle.