I'll echo the thoughts of others here, if this is your first traditional kilt, you will need to practice managing the pleats, to avoid sitting on a heap of tartan. You need to get to the point at which "sweeping the pleats" is automatic, when sitting, etc.

Getting in a car will be a challenge initially. Putting one foot in first is the route to the aforementioned heap of tartan. Open the door wide, sit sideways on the seat, remembering to sweep the pleats, then swing both legs in together. This is a whole lot easier on leather or vinyl seats but a plastic bag can help on cloth seats. Be careful not to catch the seat back with any of your buckles.

I'd also say avoid eating out in it before the wedding, restaurant napkins are rarely gig enough to cover the whole kilt.

Getting some practice will also get you used to the reactions of the populace at large - you will get a lot of second takes!