According to the Wikipedia article on vocal range, E2-E4 is the general range for a bass, whereas the general range for a baritone is G2 - G4.
I've been singing in choirs for over 40 years and have always sung bass. My range is roughly E2 - E4 as well and I'm most comfortable from F2 - A3.
That said, there is a fair amount of overlap between bass and baritone ranges and at the relatively young age of 18, I wouldn't worry too much about defining yourself. If you are not singing in a choir or an ensemble it doesn't really matter anyway. Any particular song or part will either be comfortable for you or not, regardless of how you label yourself. If you do audition for a choir, the director will most likely take you through the audition process and then decide which part would best suit you.
If you have the time, means and inclination to do so, I would strongly recommend taking voice lessons so that you learn proper singing technique and don't develop bad habits. If you take voice lessons, you might find that you can extend your range even more beyond where it is now.