So, what should i do against Irelia if I don't stomp her pre-7?

As rumble the stun does suprisingly little execpt keeping you in range as your flame thrower is active even when stunned. Sure this might not be enough but buy health/armor and sit back and farm with your e if you feel like she does too much damage. If irelia wants to zone you on e distance she has to q you directly so she slows instead of stunning with her e (there is a big difference between q to minion + stun + q when you get out of range compared to q directly + maybe stun) and with your shield + range on your abilities you should be able to survive that a couple of times while dealing decent damage. If all else fails go mid lane and push there or force fights at dragon. Irelia is not too good in teamfights before trinity force compared to rumble (sheen was her last major powerspike) and even if she has a triforce a good rumble ult is game changing. If you are not too far behind calling your jungler for help when she pushes is also a good way as she has no escape beside her tenacity passive.

Also remember a rylais does wonders for peeling and utility even if you are behind. (this one has nothing to do with the matchup but everyone seems to forget this)

EDIT: sorry for the wall of text but i hope this helps