Can't decide!

Someone tell me it will be ok and go back to my book! I have 2 pairs of sleepover patterns on the cutting table. I want to use some out of print fabric, so I want Maria to be able to wear them a few years. I think technically she is in between size 4 and 5, but I can't decide if I should make a size 6, and adjust the elastic as needed? Or just make a 5? (She's worn her 4's for the last 2 years at least and they are just now way too short. ) But the 6s might be a touch too long right now. I've been sick for a week, and dh is on a business trip until thursday. I should just go back to bed and wait for pretty fabric to show up at my door while in my cough suryp induced indecisions. (Haha I had to order the trim for one of my pj pairs).