Should I get married? My guy is leaving for basic training in less than 4 months and i'm feeling the pressure!?

We met a year & 7 months ago & we hit it off immediately. He was all I wanted in a guy and still is. I was previously in a horrible relationship for 5 years that went sour. He makes me happy for the most part even though we have our differences. He brought up marriage after a year into the relationship and i knew then i wasnt ready and said we should wait it out for a couple years r so but he decided to join the airforce & he knew he would be leavin within 6 months and wants to marry before he leaves. I now know and feel like im ready but Still i have doubts and get anxiety everytime i think of the thought of saying i do. People say if u have doubts u shud wait. I am 23 and hes 25. I dont know what to do because i feel uncertainty And maximum pressure since he wants to marry within 4 months what should i do?