Dildo help 😓🍆

So I recently bought myself MY VERY FIRST dildo. It's 8" long, 1.1" thick, light sparkly purple, flexible, soft and veined! I love this thing! I managed to fit it all in in the first try after plenty of lube and gentleness. No discomfort, feels good but still getting used to it.  HERES THE PROBLEM: I've been having trouble with not being able to orgasm while using it. Now I'm no newbie to masturbation (penetrative, too) or orgasming. Done it before but this thing isn't making me O! Why? Is my body just getting used to this new toy? Have I orgasmed without realizing it (I've felt very close to doing so), or maybe I've not done enough "self-foreplay"? Any ladies who've experience with dildos please help this dildo newbie out!