Check your I-140 approval notice and if you find this notation in the Notice Type box: "Mem of Profession w/Adv Deg, or of Exceptn'l Ability Sec. 203(b)(2)." , then you are EB2 category; if it is this notation: "Skilled Worker or Professional, Sec 203(b)(3)(A)(i)" or "(ii).", then you are EB3.