"There are many health problems that can impact fertility that a person can be aware of long before TTC."
Not only gynae conditions like endo , pcos, fibroids but also thyroid conditions, surgical mishaps, ovarian torsion, poor ovulation, premature menopause, certain medications for other conditions, cancer treatment...
Also entirely possible without your knowledge that in "just a few months" she has already experienced a loss.
If you got married around the same time and both been ttc even without her having reason for concerns re her fertility it can still be annoying that you got pregnant first. Not only do you not know for a fact she said she was jealous even IF she said it you don't know the tone. It could have been lighthearted - as in "I can't wait to get pregnant myself" or sarcastic as in "so what".
She may even "just" be struggling with feeling really broody and her husband not yet feeling ready.
It doesn't sound like you know her hardly at all so no way you'd know and even the people who know her better may not know if they're struggling to conceive (a lot of people keep such info to immediate family and even just between them and their partner!) or they're not telling you cos it's none of your business.
Quite honestly you're coming over as self absorbed and arrogant.
You're colleagues not friends. I also find it a bit weird that you "announced" your pregnancy. When I was pregnant I told my boss and gradually others as it became more obvious, didn't feel the need to "announce" it at all. - ah see you're backtracking on that info. Plus telling only those that haven't had losses is very poor handling too. They'll still find out but not from you. But then maybe that's your aim.
I'd had a mc when I'd not long been working at one job, one of the other ladies had struggled for many years and was undergoing ivf, was successful - know what she did? Brought me a cuppa and told me second privately so if it was upsetting I wasn't upset in front of others or caught out by hearing the news. Perfect choice in my opinion. She did similar with another colleague who'd had a stillbirth, told her first, who also appreciated her sensitive handling of a difficult situation.
Your pregnancy. While lovely happy news for you is not the sun, the world, even your workplace does not revolve around it.
I'm guessing you're fairly young, it IS gossip discussing other colleagues especially in a negative way and it's wise not to indulge. For several reasons:
If someone is gossiping TO you chances are they're gossiping ABOUT you too - for all you know your "good friend" is going to this colleague and saying "op thinks you're a cow for not congratulating her on her pregnancy and that you're jealous" - I learnt this lesson the hard way when younger
If you repeat anything without absolutely verifying it, YOU become a gossip
If your bosses/clients hear about it, it looks (because it is) deeply unprofessional, a distraction from your work, can even open you up to accusations of bullying/harassment in the workplace - I've seen it happen.