HMA is still a low age.
Last time I was in Iron age I stayed there about a year. Got the Triad, OBS, Traz, ToR, LoA, StM. CF, HC,, Cape, up through their sweet spot and Arc to 80. Also had TA, AO, and Kraken at lvl 10. I did not need any houses, supply or goods buildings as I had put in the Event building I got through the year. I also built up my FP stash and had built up my goods inventory to have enough to cover me needs and more to spare for both Iron Age and EMA. I also made sure I had a good amount of One up and Reno Kits, And a supply of rogues. First thing I did on moving up in every age was upgrade my Champion so Traz would spit them out until I got the troops for my new age.
The important thing is to build up forward strength and keep that going as you age up. Once I did move out of Iron age I did not rush, but kept a steady pace. only staying long enough in each age to gather enough goods to complete all the techs for each following age. (usually 2 - 3 weeks, never more than a month) And get into the top 5 in my hood. And auto battle all of GE. I then stopped in PE as I like the troops there for fighting. (Some prefer Indy) Camped there until I had worked all my military GBs up to 75 and the support ones to 60. Continued to upgrade Event building if better came along. Or build more of the ones I liked. Plus really build my FPs and goods up for ME, PME, as the troops in both suck. So wanted through them quick Only spent a week in each. Spent a little longer in CE, and TE to make sure I kept my forward strength up. Then got to FE. Which is a great age to camp in, to really get strong as you have Hovercraft there to fight with which are awesome.