There’s one of those things you learn early on in your career as a programmer: be very careful of the estimates you give.
If you ever give an estimate in passing, you can be expected to be held to that regardless of how the scope of a project may change.
Project planning is a hard task. If you say 4-6 months of effort, the people above you immediately think “3-4 months… because you’re sandbagging.” Everyone else thinks “6-8 months… because it’s way harder than it looks.”
And now you’re stuck in the middle.
Yes, estimates are needed. But at the same time you need to treat them as you would a stick of dynamite that may go off at any time.
Handle with care.