Versatile Mage: I'm Zhao Manyan's Big Brother

[Transmigration + System + Multiple Heroines + Starting from Birth] The early chapters take their time introducing what he did as a child. He transmigrates from the start and becomes the eldest son of the Zhao family, as well as the older brother of Zhao Youqian and Zhao Manyan. The System doesn't arrive until he starts high school and awakens his magic! ... (I'm out of ideas)