Hello and welcome Omen. I don't know how well you know this girl, or what your relationship with her is. If she's on your mind a lot in real life, then it's only natural that you would dream about her. The dream doesn't necessarily mean that you have romantic feelings about her, just that she's on your mind somehow. The dreams could have all mixed up components, for example, you could have her in the back of your mind and at the same time be jealous of someone else for something totally unrelated, so it turns into a dream about jealousy that involves her. It would be very normal to have a dream about jealousy that involves your brother; there are all sorts of reasons for siblings to be jealous of one another in real life.

Or some aspect of this girl's looks, personality, etc. could subconsciously remind you of something in your life that your mind is trying to bring to the surface.

It's really hard to tell without knowing more details about your relationship with this girl in waking life.