I very strongly recommend tackling an area of logic (or indeed any new area of mathematics) by reading a series of books which overlap in level (with the next one covering some of the same ground and then pushing on from the previous one), rather than trying to proceed by big leaps.
In fact, I probably can’t stress this advice too much, which is why I am highlighting it here. For this approach will really help to reinforce and deepen understanding as you re-encounter the same material from different angles, with different emphases.
The author of the Teach Yourself Logic study guide agrees with you about reading multiple sources: