Little House on the Prairie S06E21 - Sweet Sixteen

When a teacher in a neighboring town gets injured, Laura is able to earn her teaching certificate a few weeks before her 16th birthday. As a result, Almanzo starts to see her as a mature adult, However, that causes a misunderstanding when, one day Almanzo surprises Laura with a visit at the schoolhouse and he suspects a student is making romantic advances toward her. Things get straightened out on her birthday when Charles helps explain what happened.