Shen is a good pick overall, but you might be more of a support than anything else, he's really good in team fights if you know how to use his taunt because you can dash and make them taunt you, making them attack you, and since you're tanky it won't do much damage but it can change a fight drastically, not to mention you can make others not feel damage for a short amount of time.
He's not really that mobile, he just has a dash like a large majority of champions in LoL, if you want somebody super mobile and can deal a lot of damage, I suggest Talon, his ult can change team fights especially in close range battles.
Offer
If you'd like I offer the service of Mentorship, I have a discord and community I'm trying to grow by being a Mentor to players, mainly to new and returning veterans but I've played this game since mid-season 1 and I've gotten to Diamond more than once, but nothing higher. You could add my league account (same IGN) or just go to my latest posts if you're interested, I have a post all about it, but it is, just an offer after all.