Absolutely, it's perfectly okay to marry someone who is younger than you. Age is just one aspect of a relationship, and it doesn't necessarily dictate the success or failure of a marriage. Compatibility, mutual respect, understanding, love, and shared life goals are far more important.
Society has made a lot of progress in disregarding age-related stereotypes in relationships. Many couples with significant age differences (in either direction) have successful and fulfilling relationships.
The key is open communication. Discuss any concerns you might have about the age difference, such as different stages of life, interests, or long-term health considerations. Remember that what really matters is your connection with each other and your shared commitment to the relationship.
Before making any serious commitment, it's important to make sure you're on the same page about key life issues, such as whether to have children, career plans, and how to handle finances. This applies to all couples, regardless of any age difference.
Lastly, what truly matters is that you're in a relationship where you feel loved, respected, and valued, where you can grow and be your best self. As long as these conditions are met, and as long as you both are consenting adults, there is no reason why the age difference should be a barrier.