I am of 28 and my penis length is 4.5" while my girth is only 3.5" erected i am worried can this girth satisfy my girl?

Don't focus: On size alone. Sexual satisfaction for a woman is far more complicated than just the size of her significant other's genitalia. It is a complex interplay of emotions and understanding a woman's likes and stimulation of multiple areas of a woman's erogenous zones. Have confidence and focus on developing a satisfying relationship with a woman and understanding what she wants/needs/likes.