Once we're saved and born again, we're just like children spiritually.--And every day a child has to eat and exercise a little more in order to grow a little more! But a lot of Christians stop growing when they are only a few years old and they never grow up, never mature! They think they've learned so much they don't have to learn any more and they never grow into the kind of mature Christians that the Lord wants each of us to be!--Real soldiers who are able to carry a lot of responsibility and make sacrifices!
God's Word says that even Jesus "learned obedience through the things which He suffered" and "He grew in stature and in wisdom and in favour with God and Man." (Heb.5:8; Lk.2:52) Every day we learn some new obedience.--And although some things get harder, others get easier--like growing up!--And that's what it's all about!
Spiritual maturity is not a matter of years or time, it's just a matter of your connection with the Lord and His Word and your obedience and your humility. A child becomes an adult when he learns to sacrifice for others and to share and help others!--That's maturity in the Lord's eyes!