OK, so what is my relation to them? I think they are 2nd cousins, but not sure:?

Generation 1: Your grandmother & her cousin = 1st cousins

Generation 2: One of your parents & cousin's children = 2nd cousins

Generation 3: You & cousin's grandchildren = 3rd cousins

It keeps going. 5 - 15 years down the road, when you have children and those grandchildren have children, they will be fourth cousins.

A cousin shares grandparents with you;

second cousins share great-grandparents with you.

The degree of cousinship is always one less than the number of generations ago.

Your grandmother's cousins would share common ancestors with you 4 generations ago, so they would be your 3rd cousins. The grandchildren of your 3rd cousins would be your 3rd cousins, twice removed.

All 3 of the above gave great answers.

Children of siblings are first cousins to each other as they share grandparents.

Children of first cousins are second cousins to each other as they share great grandparents

Children of second cousins are third cousins to each other as they share great great grandparents.

and so on.

The removes come in when you are in a different generation coming down from a common ancestor.

You are a first cousin once removed to your parents' first cousins as their grandparents are your great grandparents. Thus one generation different. You are also a first cousin once removed to your first cousins' chidren as your grandparents are their great grandparents. Again, one generation different.

Here is a relationship chart:

http://www.islandregister.com/cousin.html

Anyone that you can find has a common ancestor is related........so who is the common ancestor?

Your Grandmother and her cousin., one of their parents are siblings, so their grandparents are the common ancestor.....so it is your great great grandparents and theirs, meaning You and your relative (grandmother's cousin's granddaughters) are 3rd Cousins

They are your third cousins. You share great great grandparents.