Being brand new does not mean your first decision has to be suspect. It suggests, however, that you do your homework and try to make an informed decision at the moment. That's where it gets a little complicated since an RV is not an investment, but an expense, and the way you want to use it at the moment should dictate part of your decision. It's difficult to project where you will be five years from now, so the fact that you may change your mind along the way is part of the decision making.
The decision is both practical and emotional - you need some space to live the way you like, your critter comfort is obviously part of this, and you want to be conscious of what all that costs. Emotionally, you are going to pick colors, special features, and floor plans.
The more time you sit on the lot imaging how that works for your family on a rainy day, where your "stuff" goes, what its like to cook and shower in, and how comfortable the sleeping arrangements are, the better off you will be. There are numerous threads here on the Forum that will show you the process others went through and those will be very helpful.
At this point, you should sift as much data as you can without going mad, drive a few, park a few, and sit in a few. All this early research will serve you extremely well in the long run. You won't be sorry that you were patient - if there is one universal truth, there is always another car, house, boat, plane or RV - they never seem to run out...
Enjoy your search . We were all brand new once.
Kim