not a big deal, no big dealadjadjective: Describes a noun or pronoun--for example, "a tall girl," "an interesting book," "a big house."
informal (a matter of little importance)
不是什么大事 bú shì shén me dà shì
没什么了不起的 méi shén me liǎo bù qǐ de
It is not a big deal that your brother likes to drink a beer now and then. Knitting a sweater is not a big deal for Jane; she has been knitting since she was eight years old.