Dingerr 1/72 scale might be a bit fiddly for a first timer of your age. Stick with me, kids have got small hands, great for small stuff.I found this
HAT Industrie 1/72 British Mortar Team (WWII) # 8227www.emodels.co.uk
looks like something I could have a go at. Any idea how much putting together these things take?
Personally to see if you really could get into figure modelling, I’d go for Airfix Multi-Pose figures in 1/32 scale at reasonable prices. The lads on here will be able to advise you on modern paints and glues. Hope that’s of some help.