Yes, you can certainly marry a girl of your same age. Age similarity between partners is a common occurrence in relationships and marriages. Many couples choose partners who are close to their age, and this is entirely acceptable and legal in most countries.
In the past, there might have been certain societal norms or expectations that encouraged larger age gaps between spouses. However, in modern times, those norms have evolved, and people have become more accepting of relationships with smaller age differences or same-age partners.
Ultimately, what matters most in a relationship is the love, understanding, and compatibility between the two individuals. Age should not be the sole determining factor in deciding whether or not to marry someone.
Of course, every relationship is unique, and successful marriages can happen with partners of varying age differences. What's most important is that both partners are willing to commit to the relationship, communicate effectively, and support each other emotionally.
As long as both you and your partner are of legal age and have a genuine and healthy connection, there is no reason why marrying someone of your same age should be an issue. Society has become increasingly accepting of diverse relationships, and it is essential to focus on the strength of your connection and your shared values rather than age alone.