Growing up, I heard the following statement all the time, "If only I knew then, what I know now!" I remember thinking as a teenager that I wouldn't ever need to say that because I already knew it all. I thought I was the most mature teenager ever and that I never needed to mature more because I had already reached the height of maturity. WOW, I COULDN'T HAVE BEEN MORE WRONG! I don't know whether to laugh or cry when I think of my foolishness. Maturity is an ever growing process and can't be "maxed out" like a credit card. Now, I do believe that you can take 2 people of the same age and 1 of them might be several years ahead of the other in terms of maturity, but overall, as a general rule, one never reaches full maturity (at least in my opinion) until they die, in which they're at their full maturity because they're dead!
I believe this so much that I will confess right now that I still have some maturing to do. I'm not saying I'm immature, I'm just saying that I know from experience that in another 10 years, I'll look back and say, "If only I knew then, what I know now." This process will continue my entire life.
This also applies to Spiritual Maturity. When we come to Christ, we are "baby Christians." We've received just enough knowledge about Christ to hand over our lives to Him. As we grow in our knowledge of Christ and begin to trust Him more and more, we grow in Spiritual maturity. I think the biggest difference between growing in life maturity and growing in Spiritual maturity is that life forces us to continue to grow, where as we are more "in charge" of our Spiritual maturity. If you're not continually working at growing in your relationship with God through prayer, scripture knowledge, devotions, etc. you not only will stop growing, but you can actually regress. I pray I never again get to a point in my walk with the Lord that I become complacent. The enemy loves nothing more than to see Christians fall backwards in their faith. He doesn't have to hard on non believers because they are already where he wants them. It's believers that he has to work hard on to get them to stop walking with God. Be on guard always!
So, to my precious daughters and any other young women reading this, YOU DON'T KNOW IT ALL! You may be mature for your age, but you are not fully mature. Enjoy the innocence of your youth now and let God mold you into maturity as HE WISHES.