Yes it is. You'll be marked as an easy hit, the attackers will fight with lower Era troops just to score lower Era Towers. tt also makes it easier for Quests and DCs that require the player to win battles. Not that that matters, rabid plunderers always attack, reward or no.
I've looked at your city. and instead of giving steaming piles of cow flop bad advice, you should be asking for advice:
ProgE city, few Expansions for your Era and bad Expansion layout, poor road layout, lots of wasted space, few and low level GBs, few Special Buildings, over 90% of your mundane buildings from previous Eras.
It's obvious from a cursory glance: You raced through the tech tree and therefore are always in the lower quarter of your hood inviting attacks; you don;t go very far in GE; don;t complete DCs very often; don;t know how to fight.
In short, you are a bad player. Which is fine, one of the beauties of this game, that you are free to be as bad at this game as you want. Which I'm sure your hoodies appreciate.
But please don't give bad advice on the Forum, the bad advice manure pile is already way too high.