I would fight your first instinct (i.e.
purchasing a large sailboat and entering an unfamiliar business). Instead, I second the motion to go take
classes (e.g. through ASA). After taking each class, take your
family and replicate what you learned. For example, take the
ASA 101 basic keelboat class. After graduation, charter the same or similar sailboat and take it out daysailing by yourself with the family where you went in the class. Similarly, take the ASA 103 (basic coastal cruising) and ASA 104 (bareboat cruising) classes. After graduation, charter the same or similar sailboat and take it out by yourself with the family following the same itinerary. And so on through all the ASA classes.
Instead of
buying the big
boat now, go sailing now. Buy a manageable trailerable boat, or join a sailing club, or get involved in
regatta racing as crew, or crew for an active sailing friend. This summer you should rack up many days on the
water sailing. Make that a priority.
After ASA classes and some sailing experience, plan and execute a
bareboat charter. The location and itinerary will be different from your classes, but you should apply what you've been
learning. As you engage in different bareboat charters, select different boats so you learn what you like and dislike. I will be surprised if you don't change your mind about your target boat.
I'm excited for you and for all the fun ahead of you this summer and the coming years.