A 77-year-old Main Line woman who pleaded guilty in a hit-and-run that seriously injured a teenage bicyclist has been given at least 90 days in Montgomery County Prison. Suzanne Lammers of Villanova was visibly shaken after hearing her sentence Thursday. She asked a deputy sheriff for a wastebasket and vomited into it, and then she was taken directly to jail. Court documents say the incident happened July 15 of last year on New Gulph Road near Morris Avenue in Bryn Mawr. Her Volvo station wagon struck Andrew Mallee of Bryn Mawr, who was 13 at the time, and kept on going. She initially told Lower Merion Township Police she thought she struck a deer. The boy has recovered from serious head injuries, but his mother says he has a hearing loss in one ear, he limps after running a short distance, and he has difficulty with his balance.