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That's for the creditors to say. Since you were an established sole proprietor - your contracts are personal (meaning that you are personally liable for the contracts, debts, tax liability - everything done to date). If you form an LLC - anything done in it's name or after formation of such should be under the LLC's corporate protection thereafter. However, even if you form an LLC - many creditors, vendors, lender, etc. will mandate that you sign a personal guarantee or they might not do business with you.
So, in answer to your question - no, you will still be personally liable for any and all actions done to date.