Conversation so far:
When did Alan Kulwicki start racing?
Kulwicki began his racing career as a 13-year-old kart racer.
Was Alan Kulwicki able to race cars at the young age of 13?
Kulwicki began his racing career as a 13-year-old kart racer.

Question: What type of racing?
Self-contained rewrite: What type of racing did Alan Kulwicki do at 13?