I love all of it but they have not aged very well
I disagree. Well, from a visuals stand point I think the show still looks great. Totally unlike TOS where, when I was watching the reruns back in the early to mid 80s, the special effects, displays, analog controls, etc. all looked extremely dated. However, TNG tech-wise still looks futuristic. LCD displays, hell even Picard is seen using an tablet device. Sure, most episodes aren't special effects laden, but still look pretty good.
The problem I think, for a kid, is most episodes will be boring. It wasn't until I was older that I appreciated the stories of, for example,
The Measure of a Manand
The Inner Lightto name a couple.
It might be better served to dive into the more action-centric episodes like
Best of Both Worldsand
Yesterday's Enterprise. Although, admittedly, the impact of these won't be there if the viewer hasn't grown to know the characters well.
I dunno, tough position you're in. Also, I think the kid has to be genuinely interested in space and science to truly enjoy this stuff. Sadly, I think most people don't have that sense of wonder and awe of the universe and the potential of human-kind and thus don't quite "get" Star Trek. Thus we have the current Michael Bay Trek.