K1 and citizenship wait time ...

Generally speaking and not specifically with reference to Iran, it usually takes six months plus for a K-1 petition to be approved by USCIS. Consular processing is normally another three months. After interview and as long as there is no additional administrative processing time, a K-1 applicant is usually given the visa within one – two weeks. On coming to the US, the marriage must be celebrated within 90 days of arrival. Filing with USCIS afterwards for adjustment of status is usually at least another six months. The green card received would normally be one which is conditional, unless the adjustment of status application is approved two years or later after the date of the marriage. With conditional green cards, an I-751 application to remove the conditional basis of residence must be filed within the 90 day period before the second anniversary of the conditional residence card grant. Assuming that the couple stays together constantly and does not separate, the green card holder would be eligible for expedited citizenship three years from the awarding of the conditional residence. An application for citizenship can be filed up to 90 days prior to the eligibility date. The question of whether he can study in a university in California with K-1 status is one that he should inquire of the specific college or university as there is no uniform rule. On the one hand, the K-1 status is thought of as leading to permanent residence and so should lead to permissive schooling, but some schools may be put off by the fact that a K-1 holder is given only a 90 day period to stay in the country. 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.

It takes about 7.5 months for the I-129F to be approved.  Consular processing takes another month or two.  Once your fiancé arrives and you marry, your fiancé will apply to adjust status.  A temporary green card will follow.  After two years, you can apply for a permanent green card.  After three years of overlapping marriage and permanent resident status you can apply for citizenship.  Your fiancé can begin studying right away.