[Start at the beginning]
Personally I suck at estimating. Estimating in the number 1 reason I feel stressed and pressured. Bad estimated are, for me at least, the primary source of problems with customer satisfaction, and my personal satisfaction with my personal work in progress.
And honestly, at the project team level, estimates are so consistent bad, across so many teams that I wonder why we even bother with the pretense. Even frequent feedback doesn't seem to overcome people's inherent bias for optimism or pessimism.
The one thing I know about estimates is that if they are met, it was most likely a co-incidence.
So just because you know the likely scope - which is what you planned, plus a factor for the quality of your outputs (related to available time, politics and a whole bunch of intangibles), plus your company's very own scope creep standards and the project estimated duration...
Well, even with all that, your estimates are likely to be crap.
Maybe, as a business analyst you can absolve yourself of the responsibility of tracing estimates to actuals and making corrections.
On the other hand, as a team member you are committed to project success or you aren't.
Which is it hombre?