Sasuke was 12 when he graduated from academy lets say 1 year later Chuunin exams so he was 13.
Obito was chuunin at 11 lets say the war was 1 year later because he didnt improve much and Kakashi turned jounin when he was 12 so Obito met madara when he was 12. and he saw rin die when he was 13 maybe and if that did unlock 3 tomoe sharingan then obito is stronger then Sasuke but we have to see untill next week.
(Ages might vary)
They both new very similar Jutsu at each other age for example both knew Fire Release: Phoenix Sage Fire Technique and Fire Release: Great Fireball Technique. But Sasuke knew Chidori and we don't know what else Obito knew he could of been very skillful with Fire Style or even more talented with his Sharingan at the age of 13 than sasuke was we're just going have to wait and see..