Choking - family rant

My siblings and I took our mum out for Mother’s day lunch. He’s a confident eater, BLW from 6 months. But when his chicken tenders came out and they were really crunchy. Not something I would choose to give him but went with it and broke them in to smaller pieces. He was beside me so I didn’t notice until my mum told me he was choking. His face was getting redder and not responding how he normally would so I reacted quick and hit his back until he was ok again. He cried a little but eventually calmed down and went back to eating his lunch (not the chicken). But I was really shook up and embarrassed that this had happened, also in public and it wasn’t me that noticed. I’ve been in tears off and on all afternoon that I let this happen. But to top it all off my sister who is 10 years younger still living her best student life. Turns round and tells me my reaction and hitting him on the back was ‘a bit dramatic’ and I hurt him. Honestly fed up of her judging how I take care of my child and when I tell her to shush or she is out of place I get no apology.