OP: Based on your posts in this thread, it seems as though you are not comfortable with yourself and, therefore, experience difficulty accepting others. You have to love–or, at least, like yourself–before you can accept and love another.
If you are engaged in counseling/therapy, consider asking your therapist or counselor to help you to understand how to like, then love, yourself. Might be through an activity that promotes self-esteem/self-worth; some such activities are exercise and volunteering to help others in need including animals.
Not unusual to be age 28 and single; not unusual to use dating apps, but it is not healthy to reject others based on superficial impressions.
OP: What is your definition of maturity ?