How can you find out if my grandmother had life insurance for me?

Its best to ask your grandmother, if possible.

If your grandmother is no longer living, you may want to ask your parents if all of your grand-mother's insurance policies have been found and checked. If your parents are not sure where to look, you may want to ask them (if they have legal right) to look at your grandmother's bank statements. The bank statements may show payments to insurance companies and one of those may be a policy on you.