If I could, may I inquire about marriage and when you should be honoring your mother and father? To be specific, is it a sin against God to marry someone if the approval of your parents is not met? The reason I begin to ask is because my fiance and I plan to marry next year. I shall be 23 and she will be 21. Yes, we maybe young, but we both are Christians and both full heartedly agree that our marriage must have the involvement of God and Jesus Christ inside of it as well as in both of our lives particularly. My parents seem to have slight hesitation to us getting married, not necessarily for us being young, but seeming they wish us to be financially secure with our own place. Within the year, my fiance and I will be securing our own place and living out on our own, of course we shall be moving out of my parents house before then. But if the approval is still not met, would it still be a sin to our God in heaven to wed? Also to mention we wish to be married in church by a pastor before God.
"Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh" (Genesis 2:24).
Prior to marriage, "a man shall leave his father and mother." Prior to forming a new family there is a separation from the old family. Having the blessing (or approval) of your parents is nice, but not required by God. Your parents are a source of good advice, but when it comes to marriage, you are forming a new family and are no longer under your parent's authority. As a child you were to obey your parents. As an adult, you give your parents respect and you care for them when they get old.
In regards to your age, neither one of you are young. A hundred years ago, getting married at that age was common.