In Deu. 20:13-14, it is written,
13 And when the Lord your God gives it into your hand, you shall put all its males to the sword, 14 but the women and the little ones, the livestock, and everything else in the city, all its spoil, you shall take as plunder for yourselves. And you shall enjoy the spoil of your enemies, which the Lord your God has given you. (ESV)
יג וּנְתָנָ֛הּ יְהוָ֥ה אֱלֹהֶ֖יךָ בְּיָדֶ֑ךָ וְהִכִּיתָ֥ אֶת־כָּל־זְכוּרָ֖הּ לְפִי־חָֽרֶב׃ יד רַ֣ק הַ֠נָּשִׁים וְהַטַּ֨ף וְהַבְּהֵמָ֜ה וְכֹל֩ אֲשֶׁ֨ר יִהְיֶ֥ה בָעִ֛יר כָּל־שְׁלָלָ֖הּ תָּבֹ֣ז לָ֑ךְ וְאָֽכַלְתָּ֙ אֶת־שְׁלַ֣ל אֹיְבֶ֔יךָ אֲשֶׁ֥ר נָתַ֛ן יְהוָ֥ה אֱלֹהֶ֖יךָ לָֽךְ׃ (WLC)
My question concerns the Hebrew word הַטַּף (há-ṭáp̄) translated as "little ones" (ESV). When were these not considered "little ones" anymore? Did it have to do with age or multiple factors such as mental maturity as well?