Is that woman being right while judging our age gap?

On this site Quora, this older woman probably in her 40s or 50s is kinda criticizing me for being a 23 year old guy and liking a girl who is 19 turning 20 next month. She kept saying how the girl I like is a child and I am an adult. I kept saying she is almost 20 and in which world is 20 a child? She isn't even a barely legal 18 year old. She is literally gonna be 20 next month and I am just 23 so we are basically both in our early 20s and only 3 years 4 months apart in age according to our birthdays. She is also saying me to let her enjoy her college days and not rob her of college experience and youth as if I am some 30 or 40 year old going for her. She is in 2nd year 4th semester of college and almost 3rd year and I graduated college 7-8 months ago and I am a soon to be an MBA Student so we are both within University age and I go for several classes these days so we are both students. Why would someone criticize even 20 and 23? Why have people come so far that even a small 3 year age gap between 2 people in their 20s considered too much? We will be 19 and 23 for just about 1.5 months and finally we are 20 and 23.