Short answer

• There are 14 Gunasthanas (stages) on the Jain path to kevala jnana, not 24. The soul climbs these steps to reach omniscience, and "kevala jnana" is the final, liberated state. Some texts name the final two stages as Sayogī kevali (omniscience with activity) and Ayogī kevali (omniscience without activity). ( en.wikipedia.org)

What about women?

• Śvetāmbara (White-clad) tradition: women can attain kevala jnana and achieve liberation in the same way as men; there are celebrated female jinas in their lineage. In this view, a woman can reach the final kevala jnana stages. ( jainknowledge.com)
• Digambara (Sky-clad) tradition: traditionally they hold that the special kevala jnana required to become a Tirthankar is not available to a woman in the current cycle, so a woman would be reborn as a man to continue toward full liberation. Thus, in their framework, women are not regarded as capable of becoming a Tirthankar in the present cycle, though souls can progress through several higher gunasthanas and attain omniscience in later rebirths. ( jainknowledge.com)

Clarifying the question you asked

• The idea that a woman attains only up to the 16th step is a misunderstanding. The classical Jain map to liberation uses 14 Gunasthanas. Some discussions mention 12–14 stages for omniscience (with different naming), but there are not 24 gunasthanas. The standard framework is 14 stages, with the final stages associated with omniscience, depending on tradition (Sayogī kevali or Ayogī kevali). ( en.wikipedia.org)

If you’d like, I can point you to a specific Jain Knowledge page that discusses the Digambara vs. Śvetāmbara positions in more detail. You can read more here and here