I am actually 20, met the Lord when I was about 12. As I look back - I think that my parents and my home church had most influence on my spiritual life so far. It is very good to have your parents as your councelors and friends!
As I left home to study in university, I was more or less "forced" to press into Him, to know Him more personally, to trust Him, to pray, to put into practice the things I only knew as a theory, to hold fast on the doctrine of Christ - not just because I've learned it so, but because the Word of God said so. (Edit: "forced" - because I had just to decide whether I am going to continue to follow Jesus or will just join the flood, and I have no godly friend in the city I live in)
One of the verses I thought of in the last days was: "And because iniquity shall abound, the love of many shall wax cold." (Matthew 24:12) ... the love of many shall wax cold... I have too been discouraged, just as you said. Also when I see other people calling themselves Christians but living like the world. But don't give up! There are people who really seek Christ, deny themselfes, take up the Cross and follow Jesus! It will always cost us something, but it is nothing in comparison to Him and what He has prepared for us!
A song goes: "Count the cost, take up your cross and follow Him!" That's it! Count the cost! Even Jesus said it! I personally put myself in the place of the three lepers before the gates of Samaria (2 Kings 7). I mean there is no better place to go than God. If we stay in sin - we will die, even if one would join hands with Satan - he will still die, and the only way to life (and meaningful life) is God, Jesus Christ!
So my advice: Don't give up! Pray that God will give you godly friends! (but remember "If no one joins me, still I will follow!) Listen to mature godly people! Meditate on the Word of God, pray. "Seek those things which are above, where Christ sitteth on the right hand of God." And trust Him!
God bless you!