Just дівчина is a teen girl or a female young adult, but as soon as you add possesive adjective or "possesive noun" (noun in genitive really) (моя дівчина, дівчина мого брата) it becomes "girlfriend" :)
Подруга can sometimes imply "girlfriend", especially if you are talking with someone with whom you don't really want to disscuss your private life
Thank you, Vinnfred. I'm glad it was you who responded because I wanted to tell you (being you're Ukrainian) that I had my first spoken conversation with a Ukrainian this week! I went to a Ukrainian church here in the U.S. to buy some food and a nice woman there helped me do the transaction in Ukrainian. I wrote my words on paper, memorized them ahead of time and kept them nearby in case I forgot something. I was a little nervous, but I told myself to just go for it. So speaking in Ukrainian I told the woman I was a beginner, spoke only a little, liked Ukrainian food and wanted to buy some. I know I made some grammatical errors, but as this course predicted, I was still understood and the actual attempt to speak the language was just awesome! It doesn't get any better than that. The Duolingo lessons, along with other learning resources I have been using are paying off. Oh, and the food was great too. Смачно!
That's such a great story! Вітаю! Making my first attempts of using French in real life a couple of weeks ago in Paris I totally understand you. That's really an incredible feeling: to be actually understood :D
There was one thing I was confused about though: you went to the church to buy food?