The first time was with my wife, and the second time was with my wife and three kids, two of whom are teenage girls. We had a great time both times. We rented a 4WD vehicle and drove all over. We stayed at nice hotels tucked away in the rain forest or overlooking the ocean. We drove everywhere, and it was never a problem. The people in CR are very nice. We never felt threatened or uncomfortable anywhere. We walked around towns freely in the evenings. We went hiking, toured the rainforests, went ziplining, bathed in thermal hot springs, spent time at the beaches. It was all great, and we will probably go again some time.
We never stayed in the resorts. We wanted to get a little taste of the Pura Vida, so we deliberately stayed away from heavily populated areas, knowing that we could always drive into town if we wanted, for meals or shopping or whatever.
My only caution is to keep all of your valuables with you, or locked up in your hotel room. Violent crime is almost unheard of in CR, but theft is common - it's a third world country, after all.
But definitely go. It's an amazing, beautiful country.