Looks good, dude. I wouldn't worry too much about the slow start. Check my sig for my grow (1st attempt). I have pics of my ladies on day 17 of flower, so you can compare (near the bottom of page 5). My flowers looked about the same size are yours do on day 17, even smaller maybe.
You might simply have a lady who blooms late. I wouldn't panic unless they're still really small on day 35. Patience. They'll bloom, assuming you're checking the pH of the water, and giving them decent bloom nutes, checking temps, just general good management of your grow. I've read that some strains don't start to really flower until the final 3rd of the flowering cycle. You'll get there.
Any major light leaks? I suspect I have a little, so I plan to do a better job of sealing the box for my next grow. I'll then be able to see if leaks make a serious impact on flowering.