I doubt you can kill a hibiscus...they are quite hardy. I actually know someone who cut one down to enlarge their drive. A few years went by and the area where the Rose of Sharon once was...cracked and up grew a new one.

As for pruning...not sure you prune them while they are in bloom...but don't see you killing this if you tried.

Share a picture once you have the job done. But...wait and see from someone if you can prune it while its in bloom. I'm not sure if you can or can't.

abigailveh Looks like a very nice plant. If you prune it back now all you will get is a smaller bush but I do not believe your will get anymore blooms. I cannot tell by how you have the blooms but my guess is a Red Texas Star Hibiscus. If so it will most likely die all the way to the ground this fall. Next spring you could prune to contain it more. It should put on some nice seed pods you will be able to share unless you want to plant more of this plant.

If you could post your zone it would be easier to get help with your questions.

Thank you
Paul