There is nothing wrong with being a late-bloomer. I can understand your sadness and anxiety, but I think of my niece who is just a wonderful girl, who didn't date all through high school, university, and for a couple of years after graduation. Then she met Mr. Right. They've been living together for several years now, and the relationship seems very solid and loving.
For relationships I would look at your 7th house of marriage (and other long-term relationships,) and your 5th house which rules love affairs. With Pisces on the cusp of your 7th house, we want to look at Jupiter (traditional ruler of Pisces) and Neptune (mordern ruler.) With Capricorn on the cusp of your 5th house, Saturn will have a lot to say about love affairs. Mars in a heterosexual woman's chart also says something about the kind of man she finds attractive. Then Venus is your sense of femininity and attractiveness.
So these planets are all pretty challenged in your chart. When two planets oppose one another, at roughly 180 degrees of separation, they seem to work at cross purposes to one another. For example, Venus in Cancer wants to be warm, tender, and loving; but Saturn in Capricorn wants to be cool, practical, and aloof. Basically if we go through the list of planets identified above, we see a lot of oppositions, as well as other stressful aspects (quincunx-- the dashed green lines, indicating uncertainty or ambivalence) and sesqui-squares (dashed black lines, indicating some tension or stress.)
You may feel of two minds about prospective BFs. You may want a relationship very badly, yet not want to give up your freedom and independence. Saturn often shows where we feel limited, frustrated, or not good-enough. With Saturn in your fifth house, you may feel you are not attractive enough to have an enjoyable romantic encounter.
With your sun conjunct Jupiter in versatile Gemini and your moon in Sagittarius, you may actually enjoy your freedom more than you realize or admit.
Also, with Virgo rising, and your very strong Mercury (thinking function) in its own sign of Gemini, and your strong Saturn in its own sign of Capricorn trining your ascendant (outward personality), you may actually be pretty discriminating. That's good-- you don't have to settle for just anybody! You certainly need someone who can match your intellectual capacity.
Just now transiting Pluto is hitting your 5th house planets, so this may seem like an especially trying time for you; not only in terms of love affairs, but your ability to laugh and enjoy life more generally. Transiting Neptune opposing your ascendant may give you a lot of self-doubts at this time.
The slow outer planets take a while to move on, but their transits are only temporary. And just because you feel there must be somthing wrong with you regarding your single state, that doesn't mean you actually, objectively have a problem.
In the meantime, try a reputable Internet dating site, and do the sensible, usual things to stay in circulation.