If i delete all of my previous saves in skyrim except for my current one, will i lose my data?

As long as you have 1 saved game then all the data will remain on that 1 save. Just make sure to pick the one saved game that is in the best situation. Remember to have at least 2-3 saves after you've cleared up memory because its important to have back ups etc in case you do something wrong in game.

It's not a very good idea to have just 1 save. Esp when you're ready for a battle or a task and then you're half way through it, and decide you didn't purchase enough potions or weapons and you prety much used up everything and stuck without having enough magic or weapons or potions to beat your enemies and move forward. This way when you have atleats multiple saves or atleast keep few saves before your undertake a major task, you can go back and reload , enhance your weapons, buy potions, get more magic and go back again . I've been in situations where I've willy nelly used all my potions , magic weapons and later only to face more fierce enemies and get stuck!

Plus if there's a glitch while saving your game, (say power goes out), you're literally screwed. Your one game save will be corrupt, and that's that. You've to start all over. That's why I keep my XBOX, PS3 on UPS (haha). Imagine playing for 100+ hours and you lose everything!

And do you know that even if you don't have a hard drive, xbox allows you to use USB flash drives. These days you can get 8GB, 16gb drives for much lesser price. ther'es even 64GB I think, but that might be expensive.

As long as you keep you most current save you are fine. You just wont be able to go back in your game which is never very necessary anyway.