Are there any disadvantages to having many-column tables

It isn't so much the number of columns that makes a design unfortunate. It's whether all those columns really belong in that same table. The data normalization rules have much to say about the consequence of storing data in one table when the data is not tightly related to the key of the table.

It behooves you to learn the normalization rules and what happens when you don't follow them At some later time, it may also behoove you to learn of cases where deliberate departure from normalization rules may result in a good design. But you can't learn that until after you have come up to speed on the value of normalizing your table design.

I think you should break it into several table (normalize the table) if it possible. Then, my suggestion is, you should use index to table that you often access. Index can make query become faster. But the disadvantage is, the process when u insert new data become slower.

There's nothing per-se wrong with having 52 columns in a table.

However, if you will frequently be querying only some subset of those columns, you might find some performance benefit from storing such frequently used columns together in a table of their own without the superfluous columns present.

That said, joining with a secondary table to access the extra columns when required will impair performance (also INSERT operations will be slower across two tables), so there is going to be a tradeoff; also note that multiple tables leads to data duplication (at very least the foreign key), and will therefore consume more space overall.

You could benchmark the two approaches to see what difference arises in your own case. Personally, I'd go with a single table until performance dictates I look elsewhere.