Hello Arpita,
Your dilemma is quite common when you get to hear new aspects about yourself from others.
First & Foremost, suggest evaluate YOURSELF [on your own] your (1) Capabilities & (2) Interests. If you find a particular field that satisfies/concurs BOTH aspects, just go for it. The circumstances & limitations are something that one can handle on the way. What finally matters is Self-Satisfaction.
I have seen many people being advised [in good-faith & absolutely with no mal-intent] about aspects that take ONLY SOME of the strengths/limitations of the person involved--for the simple reason that they were exposed to ONLY those aspects of the individual. It's only the individual concerned who would know in-detail his/her overall strengths & limitations.
While taking others' inputs into consideration, the Final decision HAS TO BE YOUR'S, since it's your life & career. Quite often people tend to pass the blame onto others' advice, IF things don't work-out the way they were intended to--when they always HAD AN OPTION NOT TO TAKE THE ADVICE.
Coming to the points you mentioned, Which field/domain/function doesn't need discipline--except that the parameters could vary from function to function? One small example: My time-discipline/punctuality WILL have to be VERY GOOD if I am working in shifts than if I was in a general shift--since in a shift, apart from the work waiting for me, I will also have to relieve another person in the earlier shift, while in general shift, it's only the work that's involved. Hope you get the point.
And reg your remark 'I think HR also involves numbers', I am not sure what you mean by this--doesn't Sales/Marketing too involve numbers--in terms of targets & forecasts? Had it been a move into finance or accounts, you may have a point.
Looking @ these queries from another angle, maybe this COULD be an opportunity for you to work on your limitations?
Give it a thought.
Pl note that this is NOT to justify or sell the idea of moving to HR--just the various & different angles from where you would need to look before making a decision.
There's one point that you didn't mention--not sure if it was considered by you: in-general, decisions by HR have, relatively, MORE far-reaching effects than S&M--@ your level, which leads to the aspect--How good [or bad] are you in thinking a few steps ahead before you take any decision NOW? If your nature is to focus on the now & this, then HR may not be the right choice for you--not that this attitude can't be developed, but it takes time & depends on, like I mentioned earlier, how deep is your interest in HR. Like the Saying goes: Where there's a Will, there's a Way.
All the Best.
Rgds,
TS