Oh my gosh, I'm in exactly the same boat as you!
I've even had counselling for it, whilst I thought it was vaginismus, but I think it was jst me worrying about my awkwardness (being a virgin at 20) and so wouldn't know what to do.
I worked up to it slowly, such as inserting a finger to a point (can't get it all the way in yet), got a vibrator in quite far, and more recently put a tampon in. However, the last experience was horrible as my muscles kept clenching and holding the tampon in when i tugged on the string. Had to spent an agonising half hour in the shower pushing it out as if I was giving birth to it! Urgh!
Lube is your friend for this: I haven't gotten objects in without it, unless I'm really aroused. Good luck!