The same martial arts I'd say a little guy can do any of them, just find a good school , with good instructor(s) friendly students and it's not a requirement but always a bonus affordable pricing,
One idea might be to check out several different schools(doesn't matter if they're each a different system), judge the quality of instruction the atmosphere in the class, whethter or not it's got the right level of physical activity for you to handle ,and like I said friendly students and instructor(s),also see if they have a free trial class where you can take part for free, then after ask yourself three questions No.1 did I get pushed ?No.2 did I enjoy myself ?and No.3 is this something I'd like to commit to? it's also good to ask more other student questions about the school and ask the instructors as well so you can really know before you make a decision
BUT DO NOT , I REPEAT DO NOT GO TO A SCHOOL THAT PROMISES TO MAKE YOU A BLACKBELT IN A MATTER OF WEEKS, this school is more than likely a McDojo which is just trying to maximise it's profits by making false claims to it's students