I don't qualify as a 40 anymore as my last birthday I turned 50, but I think I qualify for your question.
First - Remember, even a Christian who is 90 can be a "new Christian." Physical age has absolutely nothing to do with Christian-age. Some people come to Christ when they are young, some when they are old.
Second - Christians are not perfect, sinless, saints. Christians are sinners who are forgiven for their imperfections, and who are struggling to become like Christ. They still face the temptations of the world, and they still deal with sin in their own life.
Third - A great many Christians are saved and then left out there without any instruction in how God wants them to live, or, worse, the only instruction they get is the type that teach only the don'ts of the old testament and none of the dos of the new testament.
This, I think, is one of the most effective tools of Satan. Christ told us that the greatest commandment is to love God, and the second is to love your neighbor as yourself. He taught that love is active. But, by causing us to ignore the "dos" of the bible, Satan causes us to violate the second greatest commandment, and in that, we automatically violate the greatest commandment for Christ said, "If you love me, keep my commandments." So if we do not show love to our fellowman, we are not showing love to Christ.
Christ said that there will come a day when people who taught in his name will be told he never knew them.
Matthew 7:
21"Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven. 22Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?' 23Then I will tell them plainly, 'I never knew you. Away from me, you evildoers!'
He also said that those who do not do the dos will be condemned.
Matthew 25:
34"Then the King will say to those on his right, 'Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world. 35For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, 36I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.'
37"Then the righteous will answer him, 'Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? 38When did we see you a stranger and invite you in, or needing clothes and clothe you? 39When did we see you sick or in prison and go to visit you?'
40"The King will reply, 'I tell you the truth, whatever you did for one of the least of these brothers of mine, you did for me.'
41"Then he will say to those on his left, 'Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. 42For I was hungry and you gave me nothing to eat, I was thirsty and you gave me nothing to drink, 43I was a stranger and you did not invite me in, I needed clothes and you did not clothe me, I was sick and in prison and you did not look after me.'
44"They also will answer, 'Lord, when did we see you hungry or thirsty or a stranger or needing clothes or sick or in prison, and did not help you?'
45"He will reply, 'I tell you the truth, whatever you did not do for one of the least of these, you did not do for me.' 46"Then they will go away to eternal punishment, but the righteous to eternal life."
Some of us, from time to time, try to do the dos.
Some work with charity organizations, some donate money to groups they believe will help, some try to use the political process to aide those in need.
Certainly we are not doing enough, but some of us do try.
