Question for extended rear-facing moms

Curious what other extended rear-facing moms would do in my shoes. I had always planned on keeping my kids rear-facing for as long as possible, which I assumed would be around age 4 or 5.

My daughter is currently 2. She has a rare genetic condition and is extremely small. They actually don’t know if her small size is because of her genetic condition (so rare there’s just not enough data to know) but currently she weighs 20 lbs 8 oz and is about 29 inches tall, so she’s about the size of a 1 year old. I would guess at her current growth rate that she won’t outgrow her rear facing car seat until she’s at least 7 or 8 years old.

Assuming we have a car that can accommodate her rear facing and assuming she doesn’t mind (which I don’t think she will), would you keep your extremely small child rear facing for that long or would you choose some arbitrary age to switch her forward facing?