Adult women in a Junior boots.

Edit: I am not asking questions about fit. I asking about the materials used to make the boots. Is the plastic or liner really any different?

Took my wife to the boot fitter, she is tiny… 5’2” and 110 lbs. size 4.5 to 5 street shoe. We both are rock climbers and experienced skiers. She is very strong. She has had a terrible time with boots packing out quick. She wears 23.5’s. This time our boot fitter put her in a Nordica Promachine Jr. appropriate flex for her skill. It was after 2 hours of trying every 23.5 LV boot tried heal wedges and fillers… still able to curl her toes, little heal lift… The cuffs looked same height as the women’s version. But, she finally got good engagement of her lower shin/ankle transition to foot bones. Which was ground breaking for her. They were one hell of deal cause they were a Jr. …

My question is will a Jr boot last as long as an adult boot? Liner looked identical to the women’s version. Cuff height is about the same. I was just thrown off by the Jr. haha, I didn’t argue because she said it’s the tightest fit she has had yet.