I don't think it is ever too late. DS didn't get the hang of latching in the hospital, and I gave him EBM for 8.5 weeks. I kept trying him at the breast, and one morning he got it! On Wednesday, he'll have been direct breastfeeding for a whole month!
I agree with seeing a breastfeeding counsellor. It is easier to get advice on positioning and getting a good, deep latch in person.
In the beginning, I had to unlatch and reattach DS frequently, he'd slip and end up nipple sucking. He is getting much better now, and when he is hungry (and therefore concentrating!) he can go an entire feed without slipping or falling off.
One thing I found helpful was to take it slowly. Make it something nice - we'd just sit together for a while, with as much skin-to-skin as possible. Before, he'd scream if I even held him close, but I'd just cuddle him close to the breast. He started being happier just cuddling, and he start having attempts. One time he just 'got' it, and has refused a bottle ever since!
Well done on expressing for your little one. It is a lot of hard work and you should be really, really proud of yourself.