How to rewrite a sentence without using "I"

Here is the sentence that I need to rewrite, without using "I". How can I do this and still have a grammatically correct sentence?

Once completion of these classes, I continued to pursue in receiving a certification.

Diana's suggestion:

Upon completion of these classes, my continued pursuit of certification followed.

I must say though, that it sounds more natural using "I".

Is this sentence being used in a resume or formal document?

This is how I would rewrite the sentence but maybe others will suggest more ways to write it.

Take care,
Diana