No, you're not right in concluding that it's too late for you to get into heaven—but not for the reason you probably think.
Let me explain by asking you a question: How good do you think you have to be before God will let you into heaven? Do you just have to have slightly more good deeds than bad deeds? Or do you have to have more than that—say, three-fourths good deeds to one-fourth bad deeds, or even 90 percent good deeds?
The Bible's answer may startle you: You need 100 percent good deeds. In other words, God's standard is nothing less than perfection, and even one sin would be enough to keep you out of heaven. This is because God is perfect, and even one sin makes you guilty in His eyes. The Bible says, "For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it" (James 2:10).
Does this mean we have no hope? No, and the reason is because of what Christ has already done for us. On the cross, all our sins were transferred to Him, and He took the punishment we deserve. Now all we must do is accept the gift God offers us—the gift of His forgiveness. Give yourself to Christ today, and ask Him to take away your sins and save you. God bless you.