You are supposed to put the definite article in front of family members when they are plural.
Mia sorella -> le mie sorelle
so I was lucky that I came through when I forgot it ;)
Oups, I forgot. Thank you for reminding me :-)
Can i say sono mie sorelle !?
Yes you can, but then you are wrong ;) See the comment of Scotthoff on top.
Mia sorella -> le mie sorelle :) thnx
What's the difference between qualle and quelle ?