I'm truly scared

First of all I know that the result of sex can be a child. Trust me I know.

But we were not planning on having one just yet.

I'm 19 (turning 20 next month) and my boyfriend is 34

(I DON'T WANT ANY REMARKS ABOUT THE AGE GAP. I LOVE HIM IT'S MY CHOICE SO DON'T JUDGE BECAUSE I'M WITH AN OLDER GUY! THANKS!)

We both have good jobs! This just happened sooner than we expected!

I have not told him yet because he travels for work and is currently in Europe.

How do I tell him? And when should I tell him? He's home in 4 days. I've known for 3 days now.