I need to write about my family history and need help on how I should start my first paragraph. Any ideas please?

Since your essay/paper will probably involve narraation,
you may wish to recreate with as much vivid detail as you can how your ancestors entered
the United States.  For instance, if your ancestors came to America via Ellis Island,
then you could, perhaps, recreate what the experience was like.  Doing some research on
this port of entry for an immigrant would be helpful in creating vivid
descriptions.

Or, you could begin in one of the ways
suggested by the link below which gives instruction on how to write an interesting
introduction.  Still, if you will make the first of your family come alive on the page,
then yours should be an interesting paper to read.