I lied to our admin now everyone in our office thinks I’m an asshole

I was a teenager when I was in a car accident and became a paraplegic. Since then, I've gone to university, earned my master's degree, married the love of my life, and we have two wonderful daughters. I work at a big company. My coworker, Chris (67M), is retiring. He's such a nice person; he's been training and mentoring me since last year. He even made knowledge-transfer videos for future employees. This man is a gem. The admin lady was talking about her favorite restaurant once, and Chris mentioned that it was his and his wife's favorite, too. So the admin lady said, "Then we are all going there for your retirement dinner." They all got excited. The thing is, this restaurant has many stairs and isn't accessible. I didn't want them to change the restaurant for me. It's his day, not mine, and not everything should revolve around me. I decided to say that I was unfortunately busy and couldn't make it. I waited until the last minute so they wouldn't find out and feel obligated to accommodate me. Instead, I decided to take Chris to lunch another day. We had a great lunch; he showed me pictures of his grandkids, his new motorcycle, and other things. The admin lady heard about it and said it was "weird" that I didn't go with them for dinner yet went to a private lunch. She asked, "If the day wasn't working, why didn't you ask to reschedule?" The truth is, I'm too embarrassed to admit I didn't want to be included because that would have meant going to a different restaurant. I would feel like an insecure idiot. I also don't want the admin lady to hate me. I feel so conflicted