My teacher recently marked on my paper not to use a gerund to start a sentence. I have been told by teachers in the past to use that format to vary sentence structure. It seems to make the paper flow better oftentimes. An example:
Learning to confront his problems is an important part of [character's] growth and maturity in the novel.
Is there a grammar rule about this? I haven't ever heard/seen one before.
Edit: It would also be helpful to know of any good examples or arguments I would be able to use when discussing this.