I want to wait to get engaged
That's interesting. Why do you want to wait to be engaged?
So I can make sure my plans are on the track first.
While marriage is important, it is also important to do everything you want to. So making sure that you are ready for marriage is good.
If a sexual relationship is not established before marriage it can lead to problems in marriage.
If establishing a sexual relationship is important to you, it is fine to do so before you get engaged. You want your relationship to be as strong as possible.