Roman leg quests

I have recently learned to play the legendary quests, with caravans which garantee a infinite spawn, but as a slow player I need to protect my city at the beginning by putting a couple of forts outside the gate leading to the enemies, to have the time to develop more with calm. And even if I take longer, I can keep it. clash and win. Instead, I have difficulty where there are more gates to the enemy and defending access to my city is impossible. I saw that if in fact they attack you already in the first 5 minutes, as in the Roman leg, I am still very unprepared. How can I cope with my playing style? Thanks for the suggestions!