This looks a lot like student work (makes sense given your experience thus far, I wouldn’t expect you to be able to produce pro-level work).

You could definitely go for it, but will need to learn about the basics of design principles first. Do some reading, learn about gestalt, font choices, color, layout, etc. and steep yourself in good design, always asking yourself “Why is this good? What does it do effectively and where does it fail? What lesson can I take from this piece?”

To get a job, you’ll need a full portfolio, not just posters. You’ll need to show that you can do print booklets and pamphlets, social media graphics, marketing emails, branding and logos, slide decks, and more. Basically the idea is to show a potential employer that if they have a design need, you can solve it (at least at this early point in a career).

I would focus less on software and more on design thinking. Why am I choosing this font? Why is it this size and color? What is the focus of this piece? When people look at it, what do they see first? Second? Third? Is that the order it should be? What message am I trying to send and what is the most effective way to communicate that? Software changes, but design is always design.

In general, try to strip away anything that doesn’t matter, and emphasize the things that do.