Looks more like a strain related issue as to why its so tall and thin, besides the fact that it doesnt look like you topped it. Ya may want to try a bigger pot as well. You can still top it if you want. The dead leaves looks like its either not getting enough nutrients from the soil, not gettin enough water, or the fertz are killing it. It could also be a simple thing, due to how low those leaves are, it could just be its earlier stage leaves dying off, which is normal..Its up to you to figure out whats wrong with it...It doesnt look too bad at all. You just should have topped it. Goodluck, peace!