You Can't Jailbreak If You're Running iOS 11.4.1
If you want to keep your iPhone SE jailbreak be sure you avoid iOS 11.4.1.
Developers have released an iOS 11 jailbreak, but the update is only available for older versions of the operating system. It also comes without Cydia.
The iOS 11 jailbreak is available for devices running iOS 11.0-iOS 11.1.2. It's not compatible with phones running iOS 11.2, iOS 11.2.1, iOS 11.2.2, iOS 11.2.5, iOS 11.2.6, iOS 11.3, iOS 11.4, or iOS 11.4.1.
It looks like at least one person has successfully jailbroken iOS 11.3, but it's not clear if it'll be released to the general public. There's a chance that it won't.
Keep an eye out for a new jailbreak information as we push toward the summer.