Please don't write conversation as celina: alexander:, etc. It's so bad and ugly to read.
You should be more than capable of having the readers naturally infer which line is being said by who in a story.
I prefer like this If it's a beginner author, because very often, when inexperiencied author try to do what you are saying , the dialogue Just became chaos, you just cant indentfy who are talking with or even If they are talking.
