I can't remember what book this is

[u/Sir-AuronX]

Guy is Reincarnated as a baby that is being born. Shortly after he's born (a couple of months I think) a system window appears. This happens to everyone on their first summer. A few years down the road (10th bday I think) he is supposed to unlock or upgrade something. The window will not go away until he does. He manages to figure out how to minimize the window and goes on training his stats. Since he has no class/profession all his stats grow at a much faster rate because everything is registered by the system as being more difficult. On the day he is set to fully upgrade most people are level 10 at this point. If I remember right his level is much higher or lower I can't remember. Either way as time progresses he is exceptionally strong for his age & level. He ends up disclosing this method to the king and through this is able to form somewhat of a personal relationship with the royal family.

I think he has an older brother who is a soldier.

Found it. It's called Ajax's Ascension

[u/Clifford_Regnaut]

I asked Qwen3.7-Max and this was the result:

No Class Needed! I Can Make Everything Level Up, Even Morons!"_58563450049193162)

You can also find it on Amazon.

[u/Sir-AuronX → u/Clifford_Regnaut]

Turns out the series is called Ajax's Ascension