At the beginning of my hair journey i startet with 2 cm. Hmm i think you could cut it a bit more, but personaly i would not feel comfortable with that because if there is a gap ore something you cant hide it and the risk of if someone can see the lace is higher with realy realy shortcut.

Here a Photo from my first atachement 6 month ago

The second photo is the shortest Toplace cut i know