Birthday and Self-test

My MIL is having her big 60th in a few weeks. She has decided to use Covid self-test to use for all attending. She's doing it outside and most people going (about 20) already gotten their Covid shots. My husband let me know that he told her he's not doing it. I've been reluctant to voice my opinion that I'm against getting tested. I've never done one and I don't support it. Besides there's a chance it's a false positive and have to get retested at a centre and go under quarantine, lose time from work, etc.

My husband said, he's fine with not going if it's a problem. But it's very important for her this year, she's been thinking about it for so long. Do you it would be fair to decline the test and still go?