Also "Do you want to try and go to the Olympics?" and "Who do you want to sail with/against?"
If the answer to the first question is "no", well, 49ers are great boats and I will forever <3 pure one-design sailing, but they're overwhelmingly sailed by early 20-somethings with O aspirations... If this is not you, consider your options! Skiffs and especially development classes like 14s do require a lot of knowledge convection to sail well. Having other well-sailed boats around is important to help you learn/develop your boat and yourself.