I have just had a very similar experience this week. Did 20 minutes in the tunnel and started my AFF course with three jumps with linked exit with instructor and then yesterday my first solo exit. It was awesome, yeah I tumbled a bit but recovery was pretty easy. Do yourself a favor and don't back out. I found the tunnel time really good for my confidence, I was also worried about spinning. If you can fly in the tunnel you will be fine. I am 54 and have left this way too long don't make the same mistake.
