Baptism and my MIL

I'm a first time mum and would like to get my son baptised. I am a pretty private person and would like to only invite my close family and friends. I was thinking of just going to church and then a casual lunch after. However my mother in law wants a big reception after so she can show off her grandson. I understand this is her first grandchild, but this is my first child too. Is it wrong that I want to keep it small and simple. Or am I depriving my son of a big event with lots of guests. What is your opinion? TIA