In I Kings 3:3 it says that Solomon showed his love for the Lord except that he offered sacrifices and burned incense on the high places. In Deuteronomy 12:4-5 God says you must not worship the Lord your God in their way, but you are to seek the place the Lord your God will choose from among all your tribes to put His Name there for his dwelling. To that place you must go. Am I correct to understand that even at this point Solomon was already sinning? Was he sinning from lack of knowlege or was he sinning from disobedience? What follows in I Kings 3 is what confuses me. If Solomon was already doing things against God's commands, then why does the passage sound like he was so wonderful, and God went out of His way to bless him? As a parent if I don't bring it to my children's attention when I first see that they're doing wrong, then it's likely they wouldn't see what they're doing is wrong and would continue in their course. If God didn't bring it to Solomon's attention that he was sacrificing to the Lord in the wrong way no wonder Solomon later on had no problem building high places for his many wives to worship their gods.
"Meanwhile the people sacrificed at the high places, because there was no house built for the name of the LORD until those days. And Solomon loved the LORD, walking in the statutes of his father David, except that he sacrificed and burned incense at the high places. Now the king went to Gibeon to sacrifice there, for that was the great high place: Solomon offered a thousand burnt offerings on that altar" (I Kings 3:2-4).
At this point in time, the temple had not been build. God did say "But you shall seek the place where the LORD your God chooses, out of all your tribes, to put His name for His dwelling place; and there you shall go" (Deuteronomy 12:5), but this hasn't happened yet. What had happened over the years is that Israel had been making offerings to God, but using the old high places instead of going wherever the Tabernacle was currently located.
This isn't what God wanted, but He had been tolerating it before the Temple was built. The passage tells us that Solomon did the same thing. It hints that God didn't like the location Solomon chose, but He put up with it. It should have been known that even in the days of the Tabernacle they were not to use the sites of idol worship for offerings to God. "Take heed to yourself that you do not offer your burnt offerings in every place that you see; but in the place which the LORD chooses, in one of your tribes, there you shall offer your burnt offerings, and there you shall do all that I command you" (Deuteronomy 12:13-14).
But you are correct that it does give us a hint as to what happened to Solomon later in life. "For it was so, when Solomon was old, that his wives turned his heart after other gods; and his heart was not loyal to the LORD his God, as was the heart of his father David" (I Kings 11:4). It is the nature of sin to be progressive. Solomon had compromised a bit altering the location of where he offered sacrifices to God. Thus, when his wives pressured him later, he eventually changed to whom he was making those offerings. Thus sin over time becomes utterly sinful (Romans 7:13).
What this continues to show is that even the great names in the Bible were not without their flaws, yet God made use of them to accomplish His purpose.