Using Spanish at work
I'm just a teenager and I got a job at McDonald's a while back, before I started practicing on Duolingo again. When I first started working, I would need to grab one of my coworkers for customers who knew little to no English. But now I'm usually fine using Spanish with customers and the kitchen staff (most of them speak mostly just Spanish). I'll occasionally forget a word, but it's never anything completely necessary. I'm really proud of what I've re-learned and now I'm motivated to keep learning! Thanks Duolingo!
If you want to know the truth. You will pick up a language faster by speaking on a regular basis. Also, you will learn more from talking than Duolingo can ever give you.
To boost your learning you can start reading articles from places like Times for kids (they have articles in Spanish), Kids book (make sure they are a little more advance).
Good luck with your studies!