automatic transmiton problem

i have 92 honda civic dx automatic and when i try to shift from reverse to drive its vary hard to shift how do i fix this problem is it my transmiton or is it just the shifter?

have you checked your trasmittion fluid lately?

i cheaked my fluid level it lil bit over im bout to flush it out n put new in but would over fill make it do that hard shifting out of reverse in to drive?