I enjoy the social aspect of running. Parkruns, Strava, meeting friends and getting coffee after etc.

Why do you need to be polite? If you’re direct or even rude you’re doing her a favour because it might turn her away from approaching other adults who would actually take advantage of her

Usually much easier if one person takes the lead yes. If you’re lucky it is obvious from the start who is better qualified or even interested in doing so.