The Bible clearly states that without holiness no one will see the Lord. As a young person, you should make a conscious decision to abstain from sex before marriage. Planning to indulge in sex and to ask for forgiveness is synonymous to playing with fire. One could easily get burnt.
1 Cor. 6:18 says "flee sexual immorality... He who commits sexual immorality sin against his own body." As our creator, God knows the best for us and He expects us to obey His word.
Be careful to play the game of deliberately committing sin especially sexual immorality, it always backfires.