As with many things, there is no black-and-white right-or-wrong answer. Focus on content, and then default to whatever style makes you more comfortable.
Content > Style
Which one of these employees would you hire:
I am someone who learns from my mistakes. I have been fired from Spacely Sprockets dozens of times for all sorts of errors, but to my credit, I have never been fired for the same mistake twice. That type of adaptability and resilience would be a credit to any organization.
George Jetson has 20 years of experience in all aspects of the sprocket industry. He has filled multiple roles in Spacely Sprockets, from Research and Design of the MiniVac, to his current role as Vice President of Sales.
Do you think employers will pick Employee A over B because Employee A uses the first-person? Focus on making sure the content is good first, as that's what you will be judged on.
Comfort > Style
Each person is going to have their preference. Some people may detest the Oxford Comma, some may love it. Title Case in Job Titles may frustrate some employers, while others may prefer it to Proper case job titles. There is no way to know who is who, so going through agonizing feats of literary acrobatics to try to avoid all potentially divisive grammatical constructions is probably going to make your content less clear.
Write however is comfortable for you. If that means first person, then great, write in first person.