Is it normal to want a sister?

If you mean a "relationship" with them in an incest way...Ew.

If you mean as in a sibling relationship, I guess I can relate, despite having a half sister.
I'm going to be moving (Yet again) to a childhood town, and who lives there? My half sister...So...That's going to be awkward.

I have sisters and I have friends who I consider to be sisters. I say your feelings are completely normal, and you can have a friend who is just as meaningful/close/reliable/loving as a sibling, so don't feel like you can never have a sister. I have been lucky with both biological and honorary siblings, and really, there is practically no difference between them as far as I'm concerned.
You could also apply to the Big Brothers, Big Sisters program, if you're old enough. It's wicked fun, emotionally meaningful, and good life experience.

I feel the same about having a brother. I have two sisters, though id also like a brother. There needs to be more testosterone in my household- also someone to carry on our family name would be nice.

You can be my sister from another mister!

Depends if you are used to all of the new gadgets and stuff at Christmas, better slow down the list. When you have another family member, your life changes. You get annoyed, more stress is in the picture... But it's always good to bring another person into this world, give them a chance and this is normal!

My brother in law got my sister, but you can probably find someone else's sister and marry her. Or you can find an only child. She may not be a sister but she's still female and has working plumbing. Although not all of them do.

Perfectly normal. My dear friend wants the same for himself.
It's normal to want what you don't have.