Well my baby girl has no name yet...i cant even decide if i want her to have my last name like my…

Well my baby girl has no name yet...i cant even decide if i want her to have my last name like my son or have their Dads (both have the same Dad)...just feel like if i give her his last name then i need to change my sons so he doesn't feel left out...Ive been on so many websites and cant decide....i just want it to b perfect! uggghhh