When you want to say that you do or act in a similar way, you should use 'too', 'either', 'also', 'as well', 'so', 'either', 'neither'. But there are a few simple rules to observe.
1) in an affirmative context we use 'too'. ''also' or 'as well', 'so', e.g.
- I can ski very well.
- I can ski very well too. (simple confirmation)
- I can also ski very well. (more emphatic confirmation)
- I can ski very well and skateboard as well (confirmation and addition).
- So can I! (inverted word order!) 2) in a negative sentence we use 'either' or 'neither'
- I don't want to go there.
- I don't want to go there either. (simple confirmation)
- Neither do I! (inverted word order!)
So, the sentence 'I'm not afraid to be a child too!' should be corrected in this way: 'I'm not afraid to be a child either!