11 week old kit still nursing?

Hi, I tried searching around for this answer but no luck:-( I apologize if this is a repeat question. Rosie is 11 weeks old today and still nursing. (Her brothers been on his own since 8 weeks.) Should I intervene? If I did seperate them, how long does mama (Lola) need for her milk to dry up? Normally I would think nature will take its course but it took me 2yrs and 4 months to wean my first child so Im feeling very sorry for Lola! Also these girls are very, very attached and cry for eachother if they are apart at all.

Thanks for your help!