I have played both
Dungeons & Dragons Board Game | BoardGameGeek and
HeroScape Master Set: Rise of the Valkyrie | BoardGameGeek with my children (ages 10 and 9). The former is particularly close to real [hack 'n slay] rolegames. Despite its name it's also actually closer to BRP than to D&D (characters use Magic Points to fuel their spells, and nothing prevents the Magic-User from using a 2H sword).
However, I haven't tried a real rolegame with them yet. I believe their attention span is still too short. I was 14 myself when I started playing D&D.