All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If you made that vow at a young age before reaching puberty, then it is not considered effective and binding unless you were discerning and able to comprehend that carrying out religious duties and obligations entails earning rewards and that neglecting them incurs punishment. In this case, it is recommended for you to fulfill your vow because the vow of a discerning boy below the age of puberty is effective and binding, and it is recommended for him to fulfill it.
Moreover, if you made that vow after having reached puberty, then it is incumbent on you to fulfill your vow and perform ‘Umrah when the thing upon which you rendered your vow conditional is fulfilled, i.e. earning money. Allaah, the Exalted, also says (what means):
{…and fulfill their vows …} [Quran 22:29]
{They [are those who] fulfill [their] vows and fear a Day whose evil will be widespread.} [Quran 76:7]
Moreover, the Prophet, sallallaahu ‘alayhi wa sallam, said: "Whoever vowed to do an act of obedience to Allaah, the Exalted, must do so; and whoever vowed to disobey Allaah, the Exalted, must not disobey Him." [Al-Bukhari]
The signs of reaching puberty for a male are:
- ejaculation of semen,
- growth of coarse pubic hair around the sexual organs, or
- reaching the age of fifteen.
As for giving precedence to marriage over performing ‘Umrah, if you do not have enough money to do both, then you should give precedence to getting married if you have a strong desire for it and fear temptation; otherwise, you should give precedence to performing ‘Umrah.
Allaah Knows best.