No. Once you enter a plea of guilty and have been sentenced on it, there is no way to go back and withdraw the guilty plea, especially after two years have gone by. I'm sorry you didn't understand the concept at the time, but as part of every plea, they take what's known as an allocution which, in sum and substance, says "I'm guilty of doing it" and then they fill in the blank with specific misdeed. If you made a specific admission, it would be extremely difficult to now go back and try to say you didn't understand and were pressured.
You had to stand before the court and agree to the guilty plea to get a lesser sentence. You had to answer questions from the judge including things like whether you had sufficient time to talk the matter over, whether you understood the ramifications of the plea, whether you agreed to waive your appeal rights, whether anyone had given you inducements to compel you to take the plea, and that you were guilty etc.
To go back and say that you want to appeal also says that you committed perjury to the court which is what makes an appeal after a plea so very, very difficult. There are avenues of appeal but it is very difficult.
Check with a lawyer in your locale to discuss more of the details.
Good luck to you.
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