My Gold Felmale Molly

Question
I have a new female gold molly I got from the Pet Store yesterday. (this is the 3rd female molly I've owned) She seems to have gotten huge over night. Now my other two females have never had babies (there is two males in the tank as well, as much as I've tried) the thing I've noticed this morning about her is that she has a little bit of white poking out close to her anal fin. My other two females have never had this happen before. Is this a sign that she's pregnant? She was already a little big when I got her, and the new gold male I got has been going to town with her since I put them both in the tank (heck, he was going to town with her in the bag from the pet store) Now I know my other molly's have mated (I've seen it for myself) but still no babies (they have been in there for over 2 months) I just want to make sure that my new one is going to be ok. I've checked my water a dozen times, and it's stop on perfect, so I just can't understand why the other two aren't having babies... and I want to make sure my new female (if she is pregnant) wont lose the babies she's caring. I know I'm asking a lot of questions, but I would really love to have some little baby molly's swimming around soon. Also... if she does have babies, should I put them in a breeding net? I have a male and female Platy in the tank as well... and I've heard that they might eat the new molly babies. Thank you for your time!

Answer
hello Stephanie.
the white dot is not a sign of pregnancy, the proper way to check is her gravid spot (located just above the anal fin) if it becomes square and big she's pregnant if its more on her chest she is just bloated. the reason the others might not be pregnant is because they are not ready so the keep the sperm inside them (which can hold for 3 months) and once they are ready will become pregnant on their own.
platys will eat the fry the very first chance they get so yes buy a net for  them to grow in for a few weeks.
it just takes time the very first minute you forget about your molly having fry they will do it.
the more you stare and wait the longer it'll take.
if they molly are no bigger than 1 inch that's why they haven't been mating, they are still too young.
just give it some time.