"il finit" is also a past form in French: it is the simple past, which does not appear anywhere else in Duolingo, as far as I know.
- present: je finis, tu finis, il finit, nous finissons, vous finissez, ils finissent
- simple past: je finis, tu finis, il finit, nous finîmes, vous finîtes, ils finirent
Well,Qiset, like gender so much in French needs to be memorised. You will get used to it all the more you practice. If I may, with respect, to begin any sentence in English we use higher case, especially on a language learning course. Fair play to you for using higher case for the pronoun first person singular "I."
It happens that "il finit" can be in present or passé simple. Duolingo decided to not teach or use the French simple past, but some users know it and added this possible interpretation.
In present: je finis, tu finis, il/elle/on finit, nous finissons, vous finissez, ils/elles finissent
In past simpe: je finis, tu finis, il/elle/on finit, nous finîmes, vous finîtes, ils/elles finirent.