At 18, you are of legal age. Are you living on your own, away from your parents, and supporting yourself?
Is your boyfriend, at age 19, living away from his parents and supporting himself? Does he have a good job, one that will provide basic living expenses (housing, food, transportation, insurance, health care)?
Are either of you in college or trade school, and if so, are you doing well (making good grades, enjoying the classes) in a major that will lead to a good job that pays a living wage? Who (or what–grant/scholarship) is paying for the college?
If you and/or your boyfriend are still dependent on your parents, you are NOT ready for marriage. You must be ready to live and support yourselves as adults.
The exception to this would be if your culture encourages young married couples to live with their parents and extended family–I know that there are cultures like this. Is your culture like this? Do you like this type of culture, or do you prefer a culture in which married couples live independently of their parents?
Finally (and you don’t have to answer here), are you having sex, or doing a lot of pre-sexual acts (petting, French kissing), etc. that are clouding your judgment and giving you the “feeling” that you are in love and ready for marriage (because you want to go all the way, if you haven’t already). Everyone who is married on CAF will tell you that good sex is not enough to keep a marriage strong–there has to be a good job and wage from at least one of the marriage partners so that married life can be safe (insurance, enough to cover expenses) and comfortable.
Think about these things.