will i feel left out if i do informal rush?

If you do informal, you likely already know st least one person because its generally invite-only. That person/those people you know will probably try to integrate you to what's going on and the friendships they have

Some pnms thrive better by experiencing relaxed informal recruitment. The stress, noise and tent talk of formal recruitment is gone. You do not have to attend parties at EVERY house. I know more than a few shy people who joined their house thru informal and were successful, contributing members beyond initiation. You can only decide for yourself whether formal or informal rush is what you prefer.

As to whether you will bond, sorority membership is life long. You will forever meet and bond with sisters from your chapters all over the USA. Each MU sorority has so many members it would be impossible to meet and be bonded with every one (except bonded by rituals and traditions of course). So please do not worry, you will more than likely find a niche within your home and grow from there.