Reluctant Bridal Shower

My bridal party consists of my sister (that lives 4 hours away) and my 2 future step daughters (13 and 16). My mom passed away almost 10 years ago and my FMIL is already helping us out with the wedding planning so much (seriously every time I see her she has something else off my list she's picked up). My sister and I have already said no to the bachelorette party and I am working to keep costs down for her since she will have travel costs for the weekend of the wedding. FH and I have been together for 8 years, we bought our house 6 years ago. I hadn't planned on having a Bridal Shower (in part because I didn't want to seem like we were gift hungry when we already have a home), but then my soon to be step daughters asked when I was planning on having my Bridal Shower. I told them that the bride didn't throw her own shower...thinking that I made it clear I didn't want one. Now they are bound and determined that they will be planning one for me. They reached out to my sister and FMIL (their Grandma) and they are legit making plans. This is super sweet, and I am honored, but I feel badly because it has inadvertently roped my sister and FMIL into funding something additional. If they (the adults roped into the hosting) are okay with this, I'm inclined to just let it be, but how do you ask that question?