Short answer
Age should be considered as one practical factor, but it should not automatically override character, faith and genuine compatibility.
Islamic Guidance
What Islam teaches
Islam places importance on religion and character rather than making age alone the decisive criterion.
Practical Guidance
What you can consider
Consider the complete picture: character, faith, maturity, health, goals and practical compatibility.
Sources
Qur'an 49:13; Sahih al-Bukhari; Sahih Muslim.