Our daughters are roughly the same age. I recently took my daughter to her first violin lesson. Suzuki. It was a nightmare. She had started daycare for the first time that week and it was at 5:30pm and she hadn't yet eaten. She was rubbing her eyes and was grouchy prior to entering the class. -I could just tell from the look on her face this was going to be challenging. She was the youngest in the class and by the end had spent most of it in the hallway with me because she was being so disruptive. Long story short, she's not even close to being ready. I'd say three or three and a half will be the right time. But there is no doubt that she'll take a few years of violin lessons. Ideally, she will enjoy it and stick with it. Like you, I would be shocked if she doesn't play an instrument as an adult. There are so many instruments in our house and she voluntarily plays all of them. I can tell, she has the desire and potentially the innate ability. ' Good luck.