@trumpetlearner
It isn't just too much pressure you have to be careful of, but over use of the lips can lead to a lip injury.
I am 84 and my chops aren't the same ones I played with back in the 50's/60's where playing a 3 hour gig was doable. These days I have to be careful of over playing. I did a 2 hour concert once with a lot of difficult ( range-wise ) material and the next day I was blowing dead air. The muscles around the chops had been damaged and were swollen. It took 3 days of applying ice packs to the chops before I could blow notes again properly.
Be careful, your virgin lips are vulnerable. If you play 5 minutes, rest five minutes. Take your time. What's the rush ? Take a good breath from deep down inside and use the stomach muscles to support the air. Blow soft, like you would if you were blowing out a candle. Play lots of long tones consisting of whole notes and half notes. Make the C in the middle of the staff an objective, but don't push it. Work your way there slowly, note by note.
And pay attention to you posture. Practice breathing with shoulders down and chest out, holding the horn with elbows pointing slightly away from the body
Good luck.
George