Looks like a papaya ....

Yes, let's talk about something like over 60 ft instead of 20 ft. Which is nothing for a tree. A walnut arising from seed would not yet be flowering at this small size.

it needs very bright light - part sun 4 hours daily will be even better. otherwise they get very leggy. watch out for scale - it loves it. it's a fast grower, so you'll need to feed it . time-release fertilizer granules work very well. it won't branch by itself, so at some point in the future you'll need to prune the stem (root the tip of course) - perhaps in a year or so.

Does anyone know the name of this plant? Thank you