Venus, ruler of the 7th, is in detriment, if you believe that to be a signifier of lack of love. More likely being at 0 Aries it merely indicates a love of freedom and excitement. She probably views relationships as being inhibiting and fears having to give up her freedom. This is in some ways echoed by the placement of the moon in Aquarius, which is not the most sentimental of placements and rather enjoys being different. An ideal partner for her will be able to continually provide her with a sense of excitement and not appear to make any demands on her freedom. There are plenty of such people in the world, but she likely hasn't had much of an opportunity to meet any of them.
There are no major aspects to any of the inner planets, so she may not be particularly personally motivated toward relationships. Yet harmonious aspects to numerous outer planets suggest that a relationship could be very beneficial to the expansion of her higher consciousness. Taurus on the descendant and Venus in the 4th also indicate the likelihood of "settling down," as long as it's in a way that does not make her feel stifled or bored, though it's anyone's guess what the time frame for such a thing might be. Some sources indicate that ruler of the 7th in the 4th can indicate marrying late in life.
On a less astrological note, 18 is very young to decide with such conviction that you never want a relationship, and since I don't see any indicators that a life of nunnery might be to her liking, I'd give her at least a few years, enough to go out in the world a bit and learn somewhat about herself as well as about others.
