Sonatine, this is what TSP is all about, how we help one another and that is what makes us so special. Everyone has different talents and ways of doing things, and you have been encouraged to have a go at making a coat which you have mastered extremely well - setting in your very first sleeve says it all. Your coat is a lovely shape, and from the photos fits very well - so well done. Now if you can master making a coat for yourself and in a reasonably short time, you surely will be able to try making lots of other garments.
As sewing has progressed over the years, different ways of making our garments has occurred, for example overlockers were once only in industry, now they are commonplace in our homes and bring an amazing amount of variety to our sewing, also sewing machines have evolved over the years and are now quite sophisticated. As you have already found out the benefits of using a 'clapper' or in your case a rolling pin when pressing wool and what a difference this has made to tame the edges of your collar, and this gadget can also be used on much thinner and even man made garments to a great effect. As you begin your sewing journey you will find many different ways of doing things - some you will like and others not so much, your sewing equipment will grow and grow - so just enjoy all that you sew.
Look forward to seeing what you are going to make next.