How it’s supposed to work:
The bride is not involved at all in the planning of any shower held in her honor. IF the hostess requests names or addresses of her dearest friends, the bride happily provides them. Other than that, the bride shows up at the time and place she is told, smiles graciously and says “Oh Thank you! You shouldn’t have!” quite often.
It’s seen as rude and gift grabby by a lot of people when the guest of honor helps plan their own shower. Since the point of a shower is to “shower” the guest of honor with gifts, it’s a bit like throwing themself a fundraiser/benefit if the guest of honor gets involved.
The shower hostess SHOULD only invite the people who are near and dear to the bride – people that the hostess KNOWS would like to give a gift to the bride.
Modern “tradition” says that only wedding guests should be invited to a shower – but traditional etiquette says the bride would have no control over that. If the hostess knows that Great Aunt Edna would LOVE to give the bride some hand-knit pot holders and welcome her to the family, then the hostess isn’t wrong to invite Edna. If the bride and groom hardly know Aunt Edna, and the MOG hasn’t suggested that Edna be added to the guest list, then Great Aunt Edna probably won’t be a wedding guest. But the bride can’t be expected to know which distant relatives will attend a shower, and she shouldn’t be held hostage to invite everyone to her wedding who is included on the guest list of a party thown by another individual.
Of course, part of the reason people lean towards inviting everyone from the shower to the wedding is because typically all of the bride’s nearest & dearest WILL be invited to attend her wedding. So if the guest list at the shower is kept very small and intimate, (as was intended when showers were first thown) then it’s quite likely that every shower guest will also be a wedding guest.
When extended family and “church ladies” attend (or throw) a shower, it’s not quite as small, and it’s at that point where a bride worries she’ll upset the ladies “who didn’t make the cut.” Avoid talking extensively about the wedding & reception and instead focus on how happy you are to be getting married, how wonderful it is that these ladies are welcoming you to the family, and how lucky you are to have met your wonderful groom. (Otherwise the conversation may drift towards “Oh, we’ll have a gigantic chocolate fountain and there will be a cirque du soliel performance… I can’t wait to see your reactions! – Oh, well not yours Auntie Edna… You’re not invited.”)
You’re OK here – just leave the planning to your Future Mother-In-Law and/or Maid/Matron of Honor, be gracious and sincere, and know that you can’t and shouldn’t be judged by your FMIL’s actions. (And if you get wind that your BFF since 3rd grade or your grandma is left off the guest list, you can probably provide their names and addresses to you Maid/Matron of Honor or Future Mother-In-Law and mention how much you would love to include them.)