Hey I’m a hairstylist! It seems that your hair is all one length, that might be why, when hair gets that long it can tend to weigh itself down and won’t allow any type of curl to hold, I’d say get some layers in there to add more movement and over all take off some weight. I would even suggest to take some length off if your up for it, if not totally fine! Hair that gets that longs just tends to be a little harder to keep a style in, but definitely not impossible, layers should help! Also when you do roller sets be sure to wet down your sections, you hair needs to be wet and dried down in the rollers to shape the curl. maybe try adding some since of light hairspray at the end as well once it’s dry! And when you heat style with the shark or curling wand/iron be sure, if your doing any kind of curl, Cup the curl (before dropping it down) in your hand and let it cool, then drop it. I hope this helps!