Dropped one of my bridesmaids

I feel like a bridezilla and that is exactly what I wanted to avoid in this wedding planning process. So I have a niece that is 19. She just had a baby in November. she agreed to be my bridesmaid when she was pregnant. so considering her and some of my other bridesmaids who may be strapped financially I decided to go be cost-effective route for my bridesmaids. I picked out a dress from Amazon for them that is great and it only cost $36. I bought all of their dresses up front in November and just let them know that they needed to pay me the $36 by February 1st. Everyone but my 19 year old niece paid me the $36. she talked to my mother and told my mother, O I need to pay for my dress don't I (this was after the deadline). My mother said well she took the dress back. My niece got upset saying why would she take it back! my mother said you never paid for it nor did you communicate to her when you were going to pay for it. She doesn't have time to babysit you. She replied "well I guess that dress is going to wait". Now I understand people have things going on in their life. Such as her new baby and the problems that she's having with that baby's father. However, she was still getting paid full pay as if she was working and gotten to the point where she was now comfortable that her baby is a little older. she told me she was going to pay for the dress one day and never sent the money. Then the next week when I asked her about it all she said was I forgot. at this point she is two weeks past the deadline of the dress and still has not communicated with me whether she will buy it or need help buying it or anything. She has asked me for money multiple times during this time. But never once brought up the fact if she can pay for the dress later or if she can pay in payments. now the dress is $36 so that's not the problem, the problem is she smokes a lot of marijuana. And she likes to boast about it on her social media as well as boast about how much money she is getting while she is on maternity leave and I feel like if you can do that and smoke so much then you can afford to pay for $36 dress. I also feel if you can ask me for money you can also let me know where you stand with this dress. So needless to say to take the stress off me I dropped her from the wedding party because I just feel that she did not care. Her own sister and mother suggested that I do this. I let her know that she was dropped and the reasons I gave her and again she still acts like she doesn't care. Basically saying it's my fault because I didn't hand hold her about the dress. So I hate that it had to be this way and I feel very bridezilla-ish which is what I was trying to avoid. I am very lenient on my bridesmaids because I want them to be just as comfortable as I am on the day. I am giving them the option of makeup, if they want it they can take it if not they don't have to, I am given them the options of how the wear their hair, I am also giving them the options of what shoes to wear, i just required them to be a certain color. there are so many other things and other dresses I could have picked but I kept them in mind and decided to keep it in the decent price range so they won't have to come out of pocket so much. but now I feel I need to be more strict because I feel I am being taken advantage of. My wedding is 4 months away and I can no longer take any procrastination or any problems. I know this is long but I just wanted to get this off my chest