As soon as comments are made for media of potential followers, that are made by exact search parameters, chosen by you (cities, hashtags, accounts' followers), not you, not we do not know, who it will be, and what media that person will post.
It depends on selected speed. On fast speed about 2000 unfollows per day are made.
When account is working, start button has a red background and label "Stop".
Note, that actions don't take place immediately, before the first actions take place, search and generation of potential follwers' list are made. On average, it takes 5 to 20 minutes.
Currently, instagram have no media organization by user's age, so we can not provide the search by this criterion.