Baby shower cost

Hi there - I'm 23 w with first baby (probably will be only baby) and my mom and I are planning the shower. My friends are not really in a place financially to do a shower for as many people as I think will come (probably around 50). They will probably contribute and bring food, help set up and clean up etc. Anyway - my question is, the place I found I want to have the shower is $500 for 4 hour rental including tables and chairs - it's a historic house and gardens, like a wedding venue. I feel bad asking mom to pay that much, I can definitely pay half but $250 is still a lot. She does have the money but I don't think she would think it was appropriate to spend that much money on a party - especially when we still have to account for decorations, cake, etc. I would not be considering this venue initially but every other idea we had has fallen through. Thoughts?