Is it normal to not want to be friends with someone

(My "friend's" name is Jamilynn)If you have saw my last post, you know where I am at. I have a "friend" who has left me either on read, or not even read whenever I text her, call, or any social media interactions. So her sister texted me wondering if I had heard from her because she said that her sister is getting annoyed easily. 1 month after (today) Jamilynn called me. I brought up the time when she said her snapchat's/texts "are not working" I brought it up and she said she forgot about the problem. What the heck! This is getting annoying.... I don't want to be friends because how can you go from not texting me at all to all the sudden call me and ask how is it going? And she di not even remember my birthday in 2 days! I am not sure if this is a friend. Her sister is very nice, but her sister is ehh, interesting, what do I do?