Went back to federal government as a seasonal GS-05 in 2016. 7 years later to the month, I'm a permanent 14.
While this seems fast, I'm 41, so more like being on track after some setbacks.
Congrats! My husband used to work for the IRS and started on the phones as a GS-05. He made it up to a GS-09 before leaving. He still has a lot of friends who work there and we were just talking the other day about how the people on the phones think getting to a GS-13 or 14 is impossible!
I find that the GS-07 to GS-09 window is a place many people get stuck, especially if they are Tax Examiners. The teams are flooded with 07's, and there are very few 08's and 09's, and those leads and managers tend not to move. The 09 managers can sometimes get 20 hours of overtime every week to fulfill admin duties, and if you add in a night-differential, they'd take a big pay cut to become a GS-11, but that creates a bottleneck for those who aren't willing to relocate.
To get over the hump, you need to make a bold move of some sort. For me, it was getting my MBA in accounting and then lucking into a
recent grad position in the Office of Chief Counsel (IRS law office). For my wife, she was a TE in ASFR and made a move to NY City at the Office of the Comptroller of Currency. Some of her co-workers were shocked she'd be a 09 so soon, but also would never consider the commute.
Someone I know made his way up from the phones in the following way: Since phones automatically ladder to 08, but the seasonal examiners only get to 08 as leads, he used his time in grade to lat-move into a seasonal lead position, which uniquely qualified him to apply for 09 Phone Lead, which then uniquely qualified him for a seasonal exam 09 management position, which then led to a phone management position. Convoluted? I'd say so, but he really worked that system.