First of all, we ask Allah to increase your zeal for doing good and to bless you with even more guidance. Making intention to dedicate one's whole life to Islam is something required of every Muslim, as Allah says (what means): {Say, "Indeed, my prayer, my rites of sacrifice, my living and my dying are for Allah, Lord of the worlds. No partner has He. And this I have been commanded, and I am the first [among you] of the Muslims."} [Quran 6:162-163]
As for the issue of arrogance or hypocrisy, it is another matter. Intending and being determined to do good are part of the religion, but praising oneself by claiming to be the upholder of religion, or mentioning that in order to receive praise from people is dispraised.
Arrogance and showing off may infiltrate any good deed, so a Muslim should not abandon doing good or refrain from being determined to do it on account of such matters; rather, he should intend to do good and do whatever good he is able to. Then, he should engage in spiritual struggle to purify his heart from the symptoms of showing off, hypocrisy, and so forth.
On the other hand, the Muslim should convey the religion of Allah to the best of his ability and knowledge, even if his knowledge is limited, as stated in the Hadeeth: "Convey on my behalf even if it is only one verse." [Al-Bukhari]
Concerning this issue, what is correct is to be on a middle course between someone who abandons conveying whatever he knows from the religion with the excuse that he is not learned – as this is not a praiseworthy form of cautiousness – and between someone who engages in false discourse about the religion of Allah with the excuse that it consists of conveying the message.
Allah Knows best.