Sheikh which course in SOK do you think I should start with as a 13 year old beginner.

1st I would like to encourage you to seek knowledge may Allah reward you and your parents for they r keen on this. However, your studying must be under your parents supervision, you can start with what they choose from the program for every Muslim and before that the important lessons by Imam Ibn Baz. Also we have a roadmap basically mad eby the brothers on the website that tells you lessons by lesson how to study the student of knowledge program.