I gather there is a whole niche in romance or erotica books that may be labeled "her first time." While I haven't read many books in this niche - most guys probably don't - I pretty certain the author has created a reasonably unique tension point for how the heroine puts her virtue aka virginity at risk. With a clearly honorable man she's just met. 
 Most of the novel hovers deliciously over the 'will-they-won't-they' emotional and actual foreplay, the author has reserved a couple of artfully crafted plot-twists for the last third of the book. 
 It took me most of two months to read the first forty percent of the novel - how much foreplay written front her POV can a guy soak up? - but I finished the second half of the story in one enjoyable rush.