If you're going to keep it in that cup, I'd flower now. That btch is going to streeetch. If you're going to pot up (which is what i would do), pot up then switch to flower in about two- three weeks.
I am but a humble man offering my humble opinion.
Cut back on the N a little, Leaves are dark green and you got some burn at the tips. Not good when your tip burns . Could be causing what looks like foxtailing to me .
Waiting for more knowledgeable members to chime in .