Advantages have no cap on the number you can take.
Your only limit is the number of disadvantages that you can actually receive points from, which is 3. Given that the book has optional rules for spending your attribute points on advantages, It seems logical that it is intended that you could theoretically continue to gain more.
To quote the book:
Each character can acquire Advantages and Disadvantages from the
following lists. Each Advantage or Disadvantage grants benefits or
inconveniences as described below. Players can spend up to 3 Creation
Points (CP) on the Advantages that he chooses and believes most
appropriate. The cost of the Advantage indicates how many CP a player
must spend to gain it. Some Advantages have variable costs, which mean
that they grant greater benefits according to the number of CP spent
on them. Disadvantages function in a similar manner, but instead of
costing a player CP, each Disadvantage gives a player Creation Points
he can spend on other Advantages. In this way the benefits and
inconveniences balance out: The more advantages you have, the greater
your problems will be. Players can choose up to three Disadvantages
for a character – although they don’t have to choose any. Unless
specifically stated otherwise, players may choose each Advantage or
Disadvantage only once.
In short, yes the sheet doesn't have enough space for some characters, especially once you consider that you can acquire more over the course of the game.
To give an example, my current existing character started with the following advantages, using a total of 7 CP. 3 from the initial points you get, and an additional 4 from disadvantages.
Total Accumulation - 2
Martial Learning - 1
Martial Mastery -2
Innate Power - 1
Ambidextrous - 1
And had the following disadvantages:
Deep Sleeper - 1
Serious Illness - 2
Severe Allergy - 1