I'm going to recline my seat in an airplane
Are you sure that you need to recline the seat that far back?
I want to put it in a more comfortable position.
While your comfort is very important, you still need to be mindful of the comfort of other people. It is rude to recline too far and squish someone, you might be hurting them badly by doing so.
I know but altitude does not give me the opportunity to have personal space.
I still think that you should at least speak with the person that you are reclining to. You should be considerate of others while you are trying to get comfortable in such a small space.