You probably should start with kitchen remodeling, since that is where the most heat is exchanged.
You cook in there, you eat sometimes, you entertain guests, do laundry, store food stuffs, keep all kinds of appliances ranging from basic to complex electrical, to simple kitchen utensils and all of that.
After you might have done all of that for long enough, the cooking space is going to start to fall apart right before your very eyes.
You may not even see it at first, but one day you will see the cracks and you will need to fix them.
Recreating your bathroom may not seem like much because there usually aren't as many fixtures, but often the two ventures tend to match in pricing because they require extensive reworking of almost everything if you are to get the best results.
Kitchen remodeling will have you changing a few appliances and equipment, and buying a number of new ones as well.
When you remodel a kitchen, you may want to redo the floors, repaint the walls, perhaps change the sink, change the countertops, and generally create more space in which you get around.
Bathroom remodeling really is not that far behind.
You may desire to install a Jacuzzi instead of the old bathtub, which is a major project that involves piping and plumbing and a lot of electrical stuff.
The floor and lavatory may also be serious works that you have to contemplate.
By and by, these two major home improvement projects are going to cost you big time, so you want to prepare for them with a budget and a workable plan.
Without them, you'd be making a big mess of everything.