Should someone get married after only knowing the other person for a period of 4 Months?

I was talking to my friend today, and i asked her how she was doing with her boyfriend. She told me great, and he asked her to marry him in quote “all seriousness.” Shes 17 and hes 24… I have somewhat kinda a big problem with this….there is no way in hell you are ready to be wed after knowing someone for 4 months..

Whats your take on this?