I have made about 4 transfers of BTC of under $100 each directly from coinbase to agora and BSM and made a couple of orders. Unfortunately I did not read into what tumbling was until recently and now I'm getting paranoid. Should I delete my coinbase account and create another one this time making sure I tumble every time? Or am I just overthinking it and should keep the same account and start tumbling from now on?
All that deleting your Coinbase account will do is add an extra line to the account info:
The rest of the data will still be in Coinbase's records.
Don't get too paranoid. Tumble from now on. The people that really need to worry are the vendors. They are the ones moving large amounts of BTC.