As Christians, as humble followers of our Lord our task every moment he allows us life is to witness to people where we are at in life: geographically, in your workplace, in your family, your community. You and I are the light on a hill, the salt that can through Christ and the Holy Spirit help change peoples lives. Understand WE do not save people. We instead are co-regents in God's Kingdom, his hands and fingers.
All of us are believer priests and must do what we can where we are to honor and serve our Lord. Do not diminish the importance of your little corner of the world. Tell people about Jesus. If you can then preach, teach, write, counsel, comfort, encourage, affirm, correct, and be an example. Saturate it all with prayer and repeat all these things everyday, every week for the rest of your life.
Don't look back, move forward.
Luke 9:62 62 Jesus said to him, “No one who puts his hand to the plow and looks back is fit for the kingdom of God.”
Run well and finish strong.
1 Corinthians 9: 24-27
24 Do you not know that in a race all the runners run, but only one receives the prize? So run that you may obtain it. 25 Every athlete exercises self-control in all things. They do it to receive a perishable wreath, but we an imperishable. 26 So I do not run aimlessly; I do not box as one beating the air. 27 But I discipline my body and keep it under control, lest after preaching to others I myself should be disqualified.
2 Timothy 4:7-8
7 I have fought the good fight, I have finished the race, I have kept the faith.
8 Henceforth there is laid up for me the crown of righteousness, which the Lord, the righteous judge, will award to me on that day, and not only to me but also to all who have loved his appearing.
17 Obey your leaders and submit to them, for they are keeping watch over your souls, as those who will have to give an account. Let them do this with joy and not with groaning, for that would be of no advantage to you.
No matter what we do in life this is our calling.
Acts 6:4 4 But we will devote ourselves to prayer and to the ministry of the word.
Matthew 28:19-20 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit,20 teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.
1 Timothy 4 :11-16 11 Command and teach these things. 12 Let no one despise you for your youth, but set the believers an example in speech, in conduct, in love, in faith, in purity. 13 Until I come, devote yourself to the public reading of Scripture, to exhortation, to teaching. 14 Do not neglect the gift you have, which was given you by prophecy when the council of elders laid their hands on you. 15 Practice these things, immerse yourself in them, so that all may see your progress. 16 Keep a close watch on yourself and on the teaching. Persist in this, for by so doing you will save both yourself and your hearers.
The reality for you and I is to recognize our limitations. Have no delusions of grandeur but commit your finite vision and energy to help God in the salvation/Christlikeness of people in your corner of the world, not to changing the world.