This again?
Your kid's tennis may have never looked back (that said, she doesn't have a twin using a 25 who you can then look into the future and assess both kids' progress, right?).
BUT: Her body, especially her tiny wrist, tiny elbow and tiny, tiny shoulder, well, they're something you may not know the truth about for 10 or 20 years.
I've said the above to you before and we've discussed it and I don't expect or even want a reply. I'm just writing it as 'the other opinion' for others reading this thread.
And before anyone says "but I learnt with a wood racquet", tennis was very different back then, with very different (lower) loads placed on joints.
Lots of good advice in the rest of this thread - light, flexible and 26 is a good option for 10ish, or the same and 27 for large 10ish to 12.
Total nonsense. There is nothing to support your statement that at smaller racquet is better or safer, nothing. Light racquets are WORSE if the kids are hitting regulation balls. It is simple physics.
Its what Rick Macci and Nick Saviano and Emilio Sanchez-Vicario have learned after decades and thousands of kids. Get kids into a racquet that is full size and designed to handle a regulation ball as soon as they can handle it, end of story. These guys have worked on this theory with numerous pediatric sports doctors and every one confirms the wisdom of a larger racquets.
Its common sense. Hitting a hard regulation ball with a light undersized racquet puts MORE STRESS on the arm. The truth is the complete opposite of what you posted.
Go try it. And try it for 6 months ....or 2 years. Go take a 23 and 25 and 26 inch racquet and hit with it, long term. Every single tennis pro who comes into our system and we require them to hit this way ends up with a sore arm. Every one of them. The smaller the racquet the sooner the pain starts.
The shorter racquets were designed for kids based on the theory that they could swing them easier...not to lessen the stress on the arm. It sounds like a good idea but it is a lousy idea. A little kid should only hit low compression balls with a short racquet....but that is not the way most use them.
Go rent a ball machine and set it on a moderate setting. Hit with a 23 inch racquet and concentrate on feeling your arm....then do it with a 25 "...then a full size. You will feel WAY more stress on your arm with the smaller racquets. It is not rocket science.
You have nothing to back up your contention that a smaller racquet is better. And until you try it yourself for at least 6 months don't try to give advice on the topic as you will be talking nonsense.
Every parent here should obey this rule. Start kids out with smaller sticks and foam balls. Then move them to low compression balls. Do NOT move them to a regulation tennis ball until they can handle a full weight racquet. Its like hitting a rock with a fly swatter.
And we are talking about weight here as much as length. If you can find a 26" that is close in weight to a full size, fine. But honestly, kids will handle the full size just fine if you let them.