In John 15:16, Jesus told His disciples that He had “ordained” them to go out and bear much fruit. In 1 Corinthians 12:18, when Paul is writing about the ministries each believer brings forth by the working of the one, unifying Holy Spirit, he used the same word Jesus used in John 15:16 when he wrote that “God sets the members in the body just as it pleases Him.”
The common word is translated into English in the John narrative as either “ordained” or “appointed”. In Paul’s letter, it is translated “set”. It describes having been put in place on purpose. You don’t climb into the place or achieve the place, you are put there. You have to get the authority, the power, the freedom, even the information of the assignment, from God.
Presuming to walk into a “calling” prevents your work from being a “calling”. When Jesus “called” Matthew (Mark 2:14) He commanded him to “follow.” When He called you, He commanded you to enter into the identity, purpose, and relationship with Him that make you complete with Him. When you began to follow Him, He then began to reveal to you the burden that He wants to use to motivate you in the calling He designed you to fulfill.
When you accepted the burden and abandoned yourself to it, following His heart in being burdened with it, He began to entrust you with a yoke that He designed just for you, just for your burden, and wants to give you abundant life through your cooperation with Him in the work that flows from your yoke being effectively fastened to your burden.
He did not invite you to drop by the agency and see what career you might be interested in pursuing. He did invite you to be part of the work He is doing in the Earth.
If you are not sure what that work is, ask Him. He wants you to know!