Are hydrogen atoms in acetone molecule acidic?
You’re not going wrong anywhere. Acetone can indeed be deprotonated. The resulting structure is called an enolate.

$$\ce{H3C-C(=O)-CH3 &lt;&lt;=&gt; H3C-C(-O^-)=CH2}$$

When compared with truly acidic compounds such as $\ce{HCl}$ and even $\ce{NH4+}$, acetone is a very, very weak acid, though. That does not mean it should be considered aprotic. Given a strong enough base — e.g. $\ce{HMDS}$ ($\ce{(Me3Si)2N-}$) — it can be deprotonated. Weaker bases will allow for partial (but probably hardly verifiable) deprotonations.