Thank you both for the kind welcome. I would love to hear a bit more about why I should skip the smaller tank and go right to the 250. Is a 250 a good choice for a novice?
Hello and welcome! The bigger your tank, the less impact that an event will have on it. Things happen in this hobby, equipment failure, user error, and so-on and success come from stability.
The thought here is simple. If you, for example, have a fish die in your 30g, and its impact was to raise ammonia and the net result through the nitrogen cycle was an increase in nitrates to 60ppm, you'd have a real problem. That level could be toxic and could cause additional die off resulting in increased nitrates and leading to a tank crash. The same scenario in a 60g, assuming things were linear, would result in only increasing nitrates to 30ppm which is much more manageable. Your event, a fish death, would likely end there and not become a chain reaction.
I'm just using this as an example to illustrate the point. It's worth noting too that things are not always linear in this hobby so the differences in my example would likely even be greater.
Common mistakes include over feeding, over stocking, poor husbandry, equipment failure, impatience, haste/over reacting, and this hobby is riddled with bad advice.
You can eliminate a lot of those variables by researching carefully, seeking advice from reliable sources before taking action, and developing routines that you adhere to religiously, but a larger tank will be more forgiving as you learn.