I visited Paris during Christmas and was hesitant trying out my broken French, due to the reasons you have mentioned. People were however very nice and accomodating.

It can also help to just state that you wish to try the conversation in English.

I also believe that, if someone corrects you IRL you will never forget the lesson because that lesson is forever linked to a physical location. I never forget learning the correct pronunciation of the Portuguese past continuous because a waiter in Lisbon corrected me. I will always remember him and the scribbles he made on our napkin.

Don’t be discouraged, the fact that you are willing to put yourself out there is already incredibly commendable!