Mandarin lesson- My family

In my family
I have 一 (One.) 姐姐 （Older sister.)
I also have 一 (One.) 妈妈 (Mum.)
I as well as that I have 一  (One.) 爸爸 (Dad.)
The last person in my family is 我 (Me.)

I don't have a 妹妹(Older brother.)