Hi @Cbendel ,
The 'average 38mbps' advertised for Faster Fibre is an average across all customers that are on that product, the actual speed you can achieve is totally dependent on the length and quality of your phone line.
If you can log into the 'My Account' site then it should show you what product you are using. Also if you can log into your router and check the connection stats then this would also prove if you were on fibre or not, you will probably see something like this in your router connection stats :
If this says VDSL then you are on a fibre connection, if this says ADSL then you are on Faster Broadband (copper wire).
You can also use this site to see what services BT think your line can support, and what maximum speeds you should be able to achieve.
For fibre (VDSL), these are the approximate maximum speeds you can expect to achieve based on your distance from the street cabinet :
