Well that sure is a tough one, but relationships and marriages are about both the parties involved. If you aren't up for something you won't be able to give it your 100% and that would lead to strain in the future. A healthy relationship is one where we understand each other and only when a couple is able to do that can they achieve a happy life together. Don't force yourself into something you know you are not ready for just to please him. Talk and make him understand why you chose what you did. I'm not saying that things can't take a bad turn because they can. But you need to take a stand for yourself here because only if you do it now will you be able to establish yourself as an equal and not a subordinate. If he does love you enough to want to marry you, he'll wait till you are ready.