My daughter started at 8, (10 now) and it was(is) hard to get gear. Went with an HJC youth helmet. All of the HJC-Y's have interchangeable cheek pads, so you can really dial it in.
For a coat, we had to do a women's XS First Gear street jacket, but the sleeves are too long. We are about to go up a size and I will bring the next one to a woman I met that works on leathers to shorten and relocate the elbow pads.
We could only find moto-cross pants, but she hates them. So, she wears old-school jeans from a western store. If only I could find the "tough-skin" jeans I grew up in
I know denim is not any better than sweat pants, but it is what it is. We do not venture onto highways or the slab...
For gloves, I bought some cycling gloves in women's small. Not armored, but full fingered and guaranteed not to fall off. Women's small and XS gloves finger's were too long.
Almost forgot about boots... She has worn western style boots, but I preferred her Doc Marten full leather type boot that cannot fall off. We are almost to the point where we can start looking at small women's boots. That is a tough one knowing they will not fit at the end of next season.
I try to stop every 30-40 min to get her moving, or she will fall asleep. She likes to sing in her helmet (says it sounds like a concert hall in there), so when the singing stops, I start looking for a place to take a break.
We will take our first moto-camping trip this next spring.
I wonder if we could start a regional/local "clothes closet" for trading/paying-forward kids gear?