Hiya! Just to let ya know, it's helpful to link the pattern you refer to:http://www.burdafashion.com/en/Patterns/Main_Collection/7642_Jacket_technical_drawing/1270778-1128998-1679669-1679829-1679831.html
Like the person who responded to your post on burdastyle, I agree that a jacket is pretty complex for a first garment. My first jacket isn't assembled completely and I started on it over 6 months ago
Got fed up with the trouble it was giving me. Since then, I've made alot of jersey-knit tops
Definitely definitely make a mock-up in a less expensive fabric (crappy old sheets or $1.50 a yard muslin works great) to make sure the fit is correct. Don't forget to transfer any changes you make to the mock-up to your pattern pieces or tracings (ya, I'd recommend tracing the pattern, too, so you don't mistakenly cut the original wrong). Um... oh ya, you might wanna google some how-tos to make adjustments to the pattern, like how to adjust the shoulder seams if you have really narrow or really broad shoulders, how to do a full-bust adjustment/full-bust alteration (if you're a C-cup or larger), how to adjust the back seams if you have a big round bum or sway-back, etc etc. Using the shorten/lengthen lines on the pattern, or grading the seams (like, smoothing the difference between two different sizse for your hips and waist) are relatively intuitive.
If you don't have the perfectly average figure, or just want to extend your skills:http://www.vintagesewing.info/
BEST sewing website evAR!
Oh ya, and because the jacket has 3 seams in the back, you should be able to adjust the fit to within an inch of it's life
Just remember that you're sposed to have room to move and stuff, not like a t-shirt. I think you're sposed to have 1 to 2 inches of ease with a jacket (eg the finished garment measurement for the bust will be 1 or 2 inches larger than your actual measurement, and will be written either on the envelope or on the front-centre piece).
Ugh, I guess I'll go finish my own jacket, now...