Mobile feat is nice and I was going to take it as well.
My opinion is two-weapon fighting is pretty poor in 5e for any class but fighter or ranger and not all that great for those classes.
Still I'll stick with it for a few and maybe take 5 lv of EK and the rest AT.
Fighting with two weapons is very useful for Rogues - it gives you the option of using your sneak attack if you fail to hit with your first attack. This is different from the Fighting Style if that's what you meant though.
Which Race is your Rogue, and what archetype are you taking at 3rd level? Swashbuckler makes the Mobile feat a little less necessary and combine it with Tabaxi Feline Agility (double movement pretty much every other turn) even more so. The 20' Climbing speed is great for mobility and natural weapon makes drawing two weapons unnecessary, with the bonus of giving you a slashing weapon when piercing is less effective - you add your strength modifier rather than Dexterity, though.
I am really enjoying my Tabaxi Swashbuckler, Jean Clawed...