当然不要说!! 原因如下:

你主动提 = 自杀:
1) 对方可能会认为你over qualified --> 家里呆着吧
2) 对方进一步会认为你还会有其它事情瞒着没讲 --> 自找麻烦

如果面试官问起四年才一个硕士:
1) was a part-time student(到此为止, 如面试官不再问)

如果面试官问起 why a part-time student:
1) 要照顾孩子(们),
2) 如没有孩子(们),就说要照顾家庭,如 LG 或 BF has been a full-time job and part-time student as well, so 我就申请了part-time student.
3)part-time student 学费 cheaper. In canada, the tuition fee of a part-time student is as half as a full time student. If you are in US, please make sure first.

建议:
1)将错就错, 但要自圆其说.(其实,你也没错,很多人都是如此起步的)
2)可以用低学位起步,用高学位腾飞.

Good Luck:)