您可以说：我毕业了。

这句话的来源可能来自中文语言中的“毕业”这个词。在中文中，“毕业”通常指完成学业，并从学校毕业。

在英文中，您可以使用各种不同的词和短语来表达这个概念，例如：

I graduated.

I have graduated.

I have completed my studies.

I have earned my degree.

I have finished school.

例句：

I graduated from high school in 2018.

I graduated from college with a degree in computer science.

I have graduated from medical school and am now a licensed doctor.

I have graduated from law school and passed the bar exam.

I have completed my studies and am now ready to enter the workforce.