Cass the years are not that much between you, but it really depends on how mature this guy is, to be honest most 19 year old males are not that mature, but there is always the exception to the rule.

Go with your feelings, some say there is nothing like having a toy boy in your life lol, you will know sooner or later if he is mature enough for you,somehow I rather doubt it though, but good luck anyhow.