My I-130 is pending. Can I come to the US on a tourist visa, and later on decide to transfer it to F1? Will that impact my I-130 in future?

Maybe yes and maybe no as the question is one of non-immigrant versus immigrant intent and the nonimmigrant statuses that you are desiring – B-2 and F1 – both require nonimmigrant intent. That being said, the waiting period for an I-130 based upon sibling relationship takes many years, and most consular officers and immigration officers are aware that a person can intend to immigrate in the future while at the same time having a nonimmigrant intent to come to the US temporarily and leave at the end of the stated purpose. You must, however, be truthful in your applications to an American consul or to U.S.C.I.S. and disclose the I-130 filing to avoid a possible charge of misrepresentation which could impact your later immigration. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.