Reconsidering my entire life, help?

I'm 20 years old. I will be entering university in september to become a high school teacher (subjects english and history) I'm "planning" on getting married in my early twenties and having kids in my late twenties or early thirties. If I have to think 20 years ahead I think I'll live a pretty ordinary life, kids, house, job, a vacation once a year, family will be a very important part of my life. And I've had this plan for quite some time and I been pretty happy with it until I saw this video.

I was just scrolling instagram before bed, and I come across this dude named GaryV and I've heard of him before, he's this motivational speaker talking about how to be a millionaire etc. And he said like "the one thing a 20-year old has that i dont have is time......." and kept going about we should get out there and experience, and try thing and fail and try again etc. etc. 

And it just really hit me, idk why, it's not like i'm not aware of life outside of myplan. I just never felt the need to explore in ways he was talking about. And this just caused me to reconsider everything. Am I dreaming to small? Do I want more for myself. I guess i'm just looking for different opinions about this