Of course Christ still has the power to forgive sins. No man has that power. A sinner has his/her sins forgiven by the Blood of Christ, which we come in contact with by doing as he has commanded.
I think we come in contact with the Blood of Christ through faith.
“Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life” (John 5:24);
“Most assuredly, I say to you, he who believes in Me has everlasting life” (John 6:47);
“Whoever believes that Jesus is the Christ is born of God” (1 John 5:1).
Imagine the situation of a person who came to Christ through faith and then was killed before baptism could be made. Even the Roman Catholics, I believe, consider that faith in Christ and true repentance will allow one to be saved at or near the point of death. And they understand baptism to be effectual in and of itself.
(RC friends, help me out here.)