If you’ve ever signed into another service using your Twitter credentials, the upcoming API shutdown may prohibit you from accessing your account. It means you should double-check whatever services you’ve used Twitter to login to, and alter your account information while you can.
Settings -> Security and Account Access -> Apps and Sessions -> Connected Apps allows you to see which services have access to your Twitter account (or, clicking here). Depending on the service, you may need to establish a new account with new credentials.
Nuke your tweets