Answer:
To be honest, this question is something you should do yourself because only you know about your mom, but I will answer you in general:
My mother would be the most important person to me in my life because she took care of me from birth, she raised me for years after years, she did her best to give me the most affordable best of the best, she gave up on many things and sacrificed many things for my sake, she always supported me and stayed by my side my whole life, and even though she scolded me or I misbehaved she never let go of me or gave up on me. All that is what makes my mother the most important and loveable person in my life.
TIP: Add some details to every point I mentioned and splint the paragraph into two. Use adjectives, similes, and more, and make your writing interesting and sincere.