MidLifeCrisis

As the name suggests I am returning to biking after a long 28 year break. I have rode various bikes from the age of 11 with a CR80 and ending with a CBR600 when I was 22. Problem I have to overcome is I lived abroad for most of that time with only 1.5 years in the UK on an NSR125 on a CBT (I think) so I have pass a full UK bike license. I have a ways to go before I can ride the bike I want and I'm just figuring out the best method to pass my license and deciding a suitable bike to start riding with the hope I can move up to a 600 and then a 1000cc. Any advice welcome on starting out and what I should do to avoid mistakes welcomed.