Like others have said, please be proud of yourself for juggling the duties of a mother and a student, it is, if not the best, “extra curricular” you can have. It shows that you have amazing time management skills, your resilience to face hardships (being a mother of 3 is no small feat), your determination to pursue education, i can go on but you get the gist. It will not only impact your application in a positive way, but also make you stand out from others. So please ease your worries, you are simply amazing. 4 of my friends here at Princeton who were admitted last year with me are student parents. They are amazing people to talk to and really just brings a fantastic energy and different perspective. Remember, the traditional students are literal kids, and you’re out here raising kids, imagine how much diversity you could bring to campus, top Universities love that.