Can't tell at this stage (or maybe when it grows up either) what it is other than a cane begonia. Close to Lucerna but I doubt it is that. Call it after your MIL until someone comes up with a name. Too many canes that look alike so enjoy it and pass it along to other family members, friends, co-workers.

I wouldn't think the light would be too much for it if it is growing extremely quickly - that is what we all want - a healthy fast growing plant. If it gets too tall for your likes, cut the top off and replant it or pass it along!