Since yours were only guesses, I offer these as considerations:Hey! I'm taking a New Testament class adn we went over this. And I thought about you
There are 5 possible reasons why Jesus was baptized. We can only guess on this aand I'm sure there's more possible reasons than 5 of them
i. He identified Himself with the sins of His people
ii. Jesus validated John’s ministry publicly
iii. Jesus marked the official beginning of His public ministry
iv. Jesus aligned Himself with the tenderhearted masses who were also baptized, rather than the hardheartedness of the Pharisees and Sadducees who refused to be baptized.
v. Jesus illustrated His death, burial and resurrection since water baptism symbolizes a person’s dying to his old life and rising to a new life in Christ.

i. A person cannot identify with someone else's sin by water baptism. But Jesus did that on the cross.
ii. A person cannot be water baptized as a validation of a preacher's ministry, John said that he was unworthy to officiate over Jesus baptism, not that he was unworthy to carry out the ministry that God had called John to do.
iii. A person cannot be water baptized to mark the official beginning of their public ministry. An ordination does that.
iv. The pharisees and sadducees were there getting water baptized by John.
v. Our water baptism illustrates our death and resurrection which could not be an illustration until after Jesus had died and risen again.
Jesus said that his being water baptized was to fulfill righteousness. Those who upheld the law in it's strictest form where there to be baptized by John, clearly it would have been a violation of Jewish law not to undergo baptism by the divinely ordained baptizer, John.