New to ant keeping

Hi I recently just caught a Lasius Niger and I heard they are very beginner friendly so that’s nice I just have some concerns

I’m 16 and wanted to do ant keeping since 14, so if you think I’m too young pls do let me know so I can let the ant go before winter.

So my concerns are just

1. I don’t think I can handle thousands of ants so what is some ethical ways to limit population growth, my friend said every month just kill a large group but that just sounded super weird and illegal (even if it’s not illegal that’s off my table)

And 2ndly if not possible what are some ant species that usually don’t have huge populations but reside in Ireland

Any questions pls do ask cheers!