Plant looks good and healthy (should post some closer/close-up shots), too early in 12/12 to expect anything other than you should see some more growth/filling in for the next week or two ("stretch" happens for the first couple of weeks of 12/12, maybe 3 depending on strain), you should also start seeing some small pistils popping up this week.
Only thing I see is it seems small for 3 months of vegging, check out my journal for comparison, the latest entry has a pic of a Blueberry (saliva dominant strain), vegged for 3 months and is now into week 7 flowering. Her colas are 33" long standing straight (I have them tied back to get more light through) and she has a bunch of them filling in with buds. Ignore the buds as I'm 3 weeks away from picking it but the point is, she's about 33"Hx24"Dx30"W.
So far good job though for your first grow, she looks healthy enough, size could be strain related but she likely didn't get enough lighting during veg, try bumping that up a bit next round.