Must one offer the vow (Umrah) before marriage, or perform expiation, or postpone marriage until after securing provision?

The vow of an immature boy is not binding unless he is discerning and intelligent enough to intend an act of devotion, in which case it is recommended to fulfill it. However, if you are an adult, it is obligatory to fulfill it when its condition is met. This is based on the Almighty's saying: [And let them fulfill their vows] and the Prophet's (peace be upon him) saying: "Whoever vows to obey Allah, let him obey Him." The signs of puberty are the emission of semen, the growth of coarse hair on the pubic area, or reaching fifteen years of age. If you do not possess enough money for both Umrah and marriage, prioritize marriage if you fear temptation; otherwise, prioritize Umrah.