What do I do with my lemon eucalyptus?

What do I do with my lemon eucalyptus?

Hi guys, I have a tiny bit of a problem regarding how I should deal with my lemon eucalyptus. I live in a flat/apartment. That means a severe lack of space. My lemon eucalyptus has grown so tall on the ledge I placed it at that I don't know what to do with it now. Its tips are touching the ceiling; problem is I have absolutely no more space to shift it around with. Should I prune it? Will pruning stunt the growth after that? Someone suggests that I should bonsai it. But I'm not sure if it'd take to bonsai-ing after almost a year of unchecked growth. For reference, two pictures:
A favorite flower.

A favorite flower.

Rose ID

Rose ID

Howdy, this is my room :)

Howdy, this is my room :)

Care of lemon myrtle

Care of lemon myrtle

Nasturtium – Alaska Mixed (flowering herb that taste peppery)

Nasturtium – Alaska Mixed (flowering herb that taste peppery)

Almost finished!

Almost finished!