actually pretty young, but i took my advantages of having a baby sister so i kept asking for presents while she grew up so i didnt spoiled it to her and then when i was 12 BAM! a baby brother so i kept going and going, i know my parents knew i knew and my sister knew but didnt said anything and havent yet, but we still get presents, thats tha cool part LOL so i´m 27 and still believe in Santa