Everybody is different, don't base your orgasm expectations on porn, these are actors, what you see is the finished product and is made up of countless stop and start takes. Some women can only achieve orgasm through clitoral stimulation but length and intensity can vary. Some women can prolong their pleasure by stimulating their nipples, although my ex found she could intensify her orgasm by holding her breath, and she had a noticeably stronger orgasm when her ass was stimulated. Have you tried setting the mood and giving yourself foreplay as it were? The main thing is just to experiment, try new things and most importantly, have fun.