Future Mother In Law?!?!?!?!?!?

Im 23, asian and have been with my bf for 2 and half years now. I met his parents straight away and we got on really well. But now the question of marraige has come up, me and my bf have agreed that we want to get financially stable and get married in about 1-2 years time. We now want to tell the rest of the family to make it official. We have spoke to my parents and they have given there blessings and really like my bf but his mum has said that she needs to tink about it? Im really confused!!! This is a love marriage not arranged and we want her blessings (his dad is cool with it)!!! I really don't no what to make of this...any ideas???? Thanx