Opinions please!

So, my sister in law is throwing me a baby shower. I said I didn't want it to be about gifts cuz to be honest they make me super uncomfortable and to sit there and open them in front of people i find awkward haha.

So we're doing a lunch thing, but I know people are going to be bringing gifts and I think her idea was to just throw them in the car and open them later... Is this rude though? Am I supposed to open them in front of everyone to "Ooo" and "awww"? Or am I ok to open them later and send a thank you?

Help please!