Congratulations! You weren't aborted, you didn't miscarry, you didn't die of SDS or childhood whooping cough or measles, you didn't die in a car crash from a lack of traffic safety or seatbelts . . . now you get to make choices for yourself.
I hope your choices include memes thanking the creators of childhood vaccines, the Back to Sleep campaign, the writers and enforcers of seatbelt laws, et cetera.
And of course, while you're thanking your mother for choosing you, ask her about how many of your close female relatives (including her) have had abortions or D&Cs. It may even be that your birth is due to one.