From what we have seen in Maya's flashbacks today she seemed to be in good terms with MJ family 10 years back... even to the point that she was tying rakhi to the man she accidentally collided with today.. seemed like she was close to that family at one point and was in visiting terms.
And from Rudra's flashback we can see he was not too young 10 years back.. may be a college going kid (late teen or early 20s).. Then how come he doesn't know Maya????
I can let go Rishi not knowing her.. since he is college going now.. so 10 years back he must have been too young..