with my little-un ( libby )(then 7 now 9), i found all rifles were far too long or heavy ( includes ultra, s200, brocock and ratcatcher, forget any springers (too hard to cock) ).
I found that,
ultra=too heavy, too long, too expensive.
S200= as above,
ratcatcher= cheap, light enough, but too long in the stock length, which could not be shortened.
All springers= too long, heavy and hard to cock and the cheap versions were absolute trash.
In the end i went for something cheap, a QB78, Co2 rifle (£120 quid), which i could cut the stock down and re-profile the grip for a smaller hand and then i painted the stock by request ( black and gold Glitter ) and infilled her name on the stock ( it needs a little fettling to get it to work very well, ( The chinese airgun forum( an english forum by fans
) has all the info and help you will need
or you could go down another route maybe?, either way, keep looking and good luck