Family Ties

so my day was going pretty normal. i went to see my grandparents and they gave me some pretty big news. I was told that my uncle (step uncle, long story) fathered three kids who are now all teenagers. and apparently had no idea. what a huge shock!! so now i have three new teenage cousin, a 15 year old girl and 13 year old twin boys. i got the mobile number of the eldest, im just not sure if i should contact her or not. i mean she is my cousin but i dont wanna frighten her or anything. i think it would be good to make contact though because shes my cousin and ive never met her. im just really unsure. what should i do? any help should be appreciated.
an important lesson learnt: don't sleep around and get pregnant by a random stranger who will leave you for 15 years and then decide to be a father. im gonna do things right when its my time.
A little shell shocked, will be okay i think. E x