If it looks like she has a 'chin' then she's pregnant. If she's been around a male at all, she's pregnant. It's a pretty good bet she's pregnant.
I have a pineapple female and her eggs are always clear, not dark, so there's no gravid spot like you see on guppies. After mine drops, you can see the eyes on the next batch about 2 weeks later. She dropped her first batch on 3/31 and has every 28 days since then. I've given away over 350 fry and have 50 more from the last drop.
If you want to try and keep the fry, you probably want to set up a separate tank, like a 10g, and buy a sponge filter and run it in your current tank for a few weeks to build up a bacteria colony, then fill up your 10 and transfer the sponge, that will speed up your cycle. Bare tank, heater, sponge filter, light, that's all you need.
Or you could just let her drop in the main tank and see if any get eaten, some fish will leave them alone, just give them cover, buy some hornwort and let it float at the top so they can hide until they're smart enough to race away from the bigger fish.
I wouldn't get a breeder box, waste of $ IMHO the fry are going to get eaten when they drop through anyways, and it's stressful on mama. The only thing those are good for is using in a separate tank where the mama is cannibalistic and turns around an eats the newly dropped fry immediately, and you won't be able to predict that behavior.
Hope this helps. I've got lots of experience w/sword/molly/guppy/platy fry so ask away.