I am 38. I have triplets pregnancy for 7week. I'm worried this situation. Is that possible that three babies carring for 36 weeks.

Yes. Most will end up in labor earlier and deliver by urgent C-section, but some get lucky. I had one mom carry to 37 wks with triplets & all did well. Just make sure you maintain good communication with your delivery team so they can work with you to get as far as possible.