Not at all.
We have free will to pursue a relationship with God or not. Satan had similar free will and he rejected God. The Bible speaks to him being cast out of heaven, but my sense is the Devil prefers his current situation, then before he was cast out of heaven, or he would not have rebelled against God. I think the same is true of us.
You want to treat homosexuality as some unique sinful behavior, rather than see it as just a natural expression of the sinful nature of man. But all sinful behavior is "natural" or we would not engage in it. We are all attracted to sin, even if how it expresses itself in each person is unique.
Heaven will be comprised entirely of forgiven sinners, not people who became life Jesus the day they decided they would pursue a relationship with God.
The key is to seek a relationship with God, it is not about which sins you have committed or whether you have sinned. Instead, as you pursue a relationship with God, we all change... whether the homosexual becomes straight or not in his or her lifetime does not determine their salvation.
God will judge and my belief is it will be whether the person truly wants to have a relationship with God, the nature of each person's sin won't be the criteria.
For most of us, some sins will be easy to walk away from others not. The desire to sin exists in all people, it is not unique to homosexuals and the desire to sin is just as compelling regardless of how sin expresses itself in one's life. As I said, everyone is born with the inclination to sin.
If a homosexual suddenly no longer felt attracted to someone of the same sex, rest assured sin would manifest itself in some other way.