Christ asks some men to sacrifice their lives to follow him as his more intimate companions. From all eternity, certain men have been called to the priesthood. It is a call inscribed in their nature, and because of this, it will bring them fulfillment.
Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in the Church until the end of time; thus, it is the sacrament of apostolic ministry. CCC 1536
If Jesus has placed a desire in your heart for priesthood, no matter your age, don’t ignore it.  Talk to a priest you admire about how you feel.