I've hurt a cat, can I be forgiven?

Q/A about it.
==========
Conversion to Islam is not hindered in any form or manner by sins committed prior to embracing Islam. So acceptance of your conversion to Islam is a function of your sincerity in embracing Allah's religion, not by what deeds are on your books. All sins prior to Islam are forgivable, and all sins after Islam — except shirk — are equally forgivable. Never despair, for Allah's mercy is far greater than our sins.

Before he became a Muslim, 'Amr ibn al-'Ās was a very strong and active opposer of Islam, as was Khalid ibn al-Walid. This was even to the extent that 'Amr ibn al-'Ās feared he would never be forgiven. The story is documented in a hadith, out of which the following quote is extracted:

‏ قَالَ ‏رَسُولُ اللَّهِ ﷺ‏ �£َمَا عَلِمْتَ �£َنَّ الإِسْلاَمَ يَهْدِمُ مَا كَانَ قَبْلَهُ وَ�£َنَّ الْهِجْرَةَ تَهْدِمُ مَا كَانَ قَبْلَهَا وَ�£َنَّ الْحَجَّ يَهْدِمُ مَا كَانَ قَبْلَهُ‏

The Prophet ﷺ observed: Are you not aware of the fact that Islam wipes out all the previous (misdeeds)? Verily migration wipes out all the previous (misdeeds), and verily the pilgrimage wipes out all the (previous) misdeeds.

_{— Sahih Muslim 121, Book 1, Hadith 228}

So, whatever sins one may have committed prior to embracing Islam will be forgiven upon taking the shahadatyn. Not only so, but with Allah's mercy, such sins may actually become good deeds in one's balance, if one repents:

إِلَّا مَن تَابَ وَآمَنَ وَعَمِلَ عَمَلًا صَالِحًا فَ�£ُولَٰئِكَ يُبَدِّلُ اللَّهُ سَيِّئَاتِهِمْ حَسَنَاتٍ وَكَانَ اللَّهُ غَفُورًا رَّحِيمًا

Except for those who repent, believe and do righteous work. For them, Allah will replace their evil deeds with good. And ever is Allah Forgiving and Merciful.

_{— Qur'an, Al-Furqan 25:70}

The main focus is to resolve not to repeat such acts again:

قُل لِّلَّذِينَ كَفَرُوا إِن يَنتَهُوا يُغْفَرْ لَهُم مَّا قَدْ سَلَفَ وَإِن يَعُودُوا فَقَدْ مَضَتْ سُنَّتُ الْ�£َوَّلِينَ

Say to those who have disbelieved [that] if they cease, what has previously occurred will be forgiven for them. But if they return [to hostility] - then the precedent of the former [rebellious] peoples has already taken place.

_{— Qur'an, Al-Anfal 8:38}

Finally, after embracing Islam, it is important to realize that as Muslims, we believe that Allah may forgive any sins we may commit, except shirk, and that it is part of our belief to never despair of His mercy:

قُلْ يَا عِبَادِيَ الَّذِينَ �£َسْرَفُوا عَلَىٰ �£َنفُسِهِمْ لَا تَقْنَطُوا مِن رَّحْمَةِ اللَّهِ ۚ إِنَّ اللَّهَ يَغْفِرُ الذُّنُوبَ جَمِيعًا ۚ إِنَّهُ هُوَ الْغَفُورُ الرَّحِيمُ

Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."

_{— Qur'an, Az-Zumar 39:53}