Has Jesus always had a physical flesh body or did he only start having one when he came into the world?
I suggest you read the first chapter of the gospel of John and see what you think.
@Rafael15 Without delving into all the mysteries of the incarnation, based upon Scripture we can say that Jesus did not have a human body prior to the incarnation. Jesus became flesh and dwelt among us and He will have His resurrected body forever (see thread below). The Lord Jesus grant you wisdom as you study. Feel free to ask more questions.
John 1:14 - The Word became flesh…
Philippians 2:7 - rather, he made himself nothing
by taking the very nature of a servant,
being made in human likeness.
Hebrews 2:14 - Since therefore the children share in flesh and blood, he himself likewise partook of the same things, that through death he might destroy the one who has the power of death…