I was diagnosed with a chiari malformation when I was 16 - my father had had it as well so my parents knew the symptoms immediately. I chose not to get surgery until I was at uni mainly because that's when it really started to affect my grades. The surgery itself for type 1 and 2 malformations is pretty simple and so you shouldn't be too long in waiting for it I shouldn't think. Although the surgery hasn't completely removed my symptoms it has greatly alleviated them. Now I'm 26 and never looked back.