……的人

者(zhě) means people who do a particular activity or with a particular attribute. for example: 初学者（chu1 xue2 zhe3）：people who just begin their learnings. beginner. 读者（du2 zhe3）：people who read. reader. 旁观者（pang2 guan1 zhe3）：people who stand and watch from the sidelines. bystander. spectator. 对此有异议者（dui4 ci3 you3 yi4 yi4 zhe3）：people who hold an objection against this

This sentence means "I'm a beginner. " zhe always come after the adjectives or verbs or some kinds of careers and doctrines. It means a kind of people. e.g Strong men. The "man"has the same meaning with 者 Beginner Same as“er”,者 is a suffix 者=....的人

Maybe you mean: 我是一个初学者。 初first学learn者er = beginner 者 then is -ist or -er. It makes the doer from the verb