I cannot comment on whether or not it is a great first H bag (it is a very lovely bag but it is open and a bit limiting to me personally so I always decided against it when being offered one), however, I can get the 18 over my shoulder but would have never worn it that way. Also, you could potentially attach a shoulder strap (think others have shown this somewhere either in this thread or on other threads on the forum) and this wear it crossbody

The look is just a matter of taste, it looked a bit stiff to me when I tried it. I would suggest to try it on in person whenever you have the chance. As with all H bags, it is quite a sum to invest, so you should be sure you will have a purpose for it. But at least the Pico will give you some options to make it work