It's a tough decision. If you're going to play this family for several generations, you'll run out of space. You've got at least 4 Sims living there now and the maximum is 8. So, if Max gets married and has a couple of kids, your house will be full until the parents die. Each generation will grow and you'll always have a full house, which is difficult to manage. You could keep your house as the homestead and always let at least one of the children live there and move the others out. It's hard to do, but it's fun in its own way because then you start to see your family around town and doing their own thing. I really like it when the ones I move out have children of their own. It helps if you know from the start that you'll be moving some of the kids out because then maybe you won't get so attached to them. If my family is wealthy, I'll get them married and sometimes pregnant and then purchase a house for them to live in with their new little family. I even use Edit Town to modify the houses in town so that they have nurseries and rooms for kids.
It really is the hardest decision I have to make when playing Sims 3, but if you're going to play this same family for a long time, it's one that has to be made.