A lot of the material that is on the PSAT and on the SAT is stuff you will learn during your Junior year. Taking an SAT during June between your sophomore and Junior year is a waste of money, in general, and, based on your PSAT 10, taking the SAT this June is not a great idea, in particular. It is unlikely that your score this June will be as high as it will be if you take the test in the second semester of your Junior year, or even next fall.
Based on your PSAT 10 scores, a score of 1400 in June is unlikely, though such a score or higher is not unfeasible for your Junior year.
My advice is to work on better test taking strategies and see what material you are missing in preparation for the PSAT/NMSQT. Take the PSAT/NMSQT in the fall, and take some practice tests in real time, and see what your scores on those tests look like. Take practice ACTs and see if you do better on those (unlike the PSAT, in which a 1400 is comparable to a 1400 on the SAT, the entire PreACT is simplified, so a 27 on the PreACT is not comparable to a 27 on the ACT).
The PSAT is cheaper, provides most of the same benefits in training for further tests, and is not reported to any college.