Should i tell her she's my sister?

Question:

Should i tell her she's my sister?

my parents were married but seperated when i was 15 months old.
my dad went on to have another daughter but i didn't find out about her until just after i turned 18.
since i found out about her i have been looking for her!eventually after so long i have an address for her but i don't know how to proceed
i don't know if she knows about me as my dad has no contact with her.
i am 24 and she is 22

as far as i know she was raised to think somebody else was her dad

any suggestions on what i should do?

i don't want to turn her whole life upside down but, at the same time, i feel she has a right to know who she really is?

what should i do??
would u want to know the truth??

Additional Details

2 months ago
we are definately sisters.we have never met as i live in ireland and she is in uk

but i have seen pictures and we look very alike

Best Answer - Chosen by Asker: 2 months ago
we are definately sisters.we have never met as i live in ireland and she is in uk

but i have seen pictures and we look very alike